/***************************************
    codeforces = topcoder = sahedsohel
    IIT,Jahangirnagar University(42)
****************************************/
#include <bits/stdc++.h>
using namespace std;
 
#define ll long long int
#define ull unsigned long long int
#define inf (INT_MAX/10)
#define linf (LLONG_MAX/10LL)
#define sc(a) scanf("%d",&a)
#define sc2(a,b) scanf("%d%d",&a,&b)
#define sc3(a,b,c) scanf("%d%d%d",&a,&b,&c)
#define sc4(a,b,c,d) scanf("%d%d%d%d",&a,&b,&c,&d)
#define fl(c,i,n) for(i=c;i<n;i++)
#define f(i,n) for(i=0;i<n;i++)
#define mem(a) memset(a,0,sizeof(a))
#define memn(a) memset(a,-1,sizeof(a))
#define pb push_back
#define aov(a) a.begin(),a.end()
#define mpr make_pair
#define PI (2.0*acos(0.0)) //#define PI acos(-1.0)
#define xx first
#define yy second
#define mxv(a) *max_element(aov(a))
#define mnv(a) *min_element(aov(a))
#define to_c_string(a) a.c_str()
#define strtoint(c) atoi(&c[0])
#define pll pair< ll , ll >
#define pii pair< int , int >
#define pcs(a) printf("Case %d: ", a)
#define nl puts("")
#define endl '\n'
#define dbg(x) cout<<#x<<" : "<<x<<endl
 
template <class T> inline T bigmod(T p,T e,T M){ll ret = 1;for(; e > 0; e >>= 1){if(e & 1) ret = (ret * p) % M;p = (p * p) % M;}return (T)ret;}
template <class T> inline T bpow(T p,T e){ull ret = 1;for(; e > 0; e >>= 1){if(e & 1) ret = (ret * p) ;p = (p * p) ;}return (T)ret;}
template <class T> inline T gcd(T a,T b){if(b==0)return a;return gcd(b,a%b);}
template <class T> inline T modinverse(T a,T M){return bigmod(a,M-2,M);}   // M is prime}
//template <class T> inline T bpow(T p,T e){__int128 ret = 1;for(; e > 0; e >>= 1){if(e & 1) ret = (ret * p);p = (p * p);}return (T)ret;}
 
int toInt(string s){int sm;stringstream ss(s);ss>>sm;return sm;}
int toLlint(string s){long long int sm;stringstream ss(s);ss>>sm;return sm;}
 
 
///int mnth[]={-1,31,28,31,30,31,30,31,31,30,31,30,31};  //Not Leap Year
///int dx[]={2,1,-1,-2,-2,-1,1,2};int dy[]={1,2,2,1,-1,-2,-2,-1};//Knight Direction
///int dx[]={-1,+1,0,1,0,-1}; // Hexagonal Direction   **
///int dy[]={-1,+1,1,0,-1,0}; //                       *#*
///                                                     **
const double eps=1e-9;
int dx[]={0,1,0,-1};int dy[]={1,0,-1,0}; //4 Direction
 
/*****************************************************************/
/// ////////////////////   GET SET GO    ////////////////////// ///
/*****************************************************************/
 
 
#define intx(i,j,k,l) ((a[i]*b[j]-b[i]*a[j])*(a[k]-a[l])-(a[i]-a[j])*(a[k]*b[l]-b[k]*a[l]))/((a[i]-a[j])*(b[k]-b[l])-(b[i]-b[j])*(a[k]-a[l]))
#define inty(i,j,k,l) ((a[i]*b[j]-b[i]*a[j])*(b[k]-b[l])-(b[i]-b[j])*(a[k]*b[l]-b[k]*a[l]))/((a[i]-a[j])*(b[k]-b[l])-(b[i]-b[j])*(a[k]-a[l]))
#define dst(u,v,x,y) sqrt((x*1.0-u*1.0)*(x*1.0-u*1.0)+(y*1.0-v*1.0)*(y*1.0-v*1.0))
#define area(p1,p2,p3) (p1.xx*p2.yy+p2.xx*p3.yy+p3.xx*p1.yy-p1.yy*p2.xx-p2.yy*p3.xx-p3.yy*p1.xx)
#define dstt(u,v,x,y) ((ll)(x-u)*(ll)(x-u)+(ll)(y-v)*(ll)(y-v))
 
int ts,kk=1;
 
#define sqr(x) ((x)*(x))
 
/// 	    0123456789ABCDEF
#define M   100006
#define MD 1000000007LL
#define MX 405
#define mid ((s+e)>>1)
#define lft ((i<<1)+1)
#define rgt (lft+1)
#define rep(i,a,b) for(int i=a;i<=b;i++)

int num,s[MX],loc[MX],row,col;
 
double a[MX][MX];
 
void gauss()
{
    int x,y;
    for(x=0,y=0;x<row && y<col;y++)
    {
        int p=x;
        rep(i,x+1,row-1) if(fabs(a[i][y])>fabs(a[p][y])+eps) p=i;
		//cerr<<x<<" "<<p<<endl;
        if(fabs(a[p][y])<eps) continue;
 
        if(p!=x) rep(j,y,col) swap(a[p][j],a[x][j]);
 
        loc[y]=x;
		//cerr<<" loc "<<y<<" "<<x<<endl;
        rep(i,0,row-1)
        {
            if(i==x || fabs(a[i][y])<eps) continue;
 
            double tmp=a[i][y]/a[x][y];
            rep(j,y,col) a[i][j] -= a[x][j]*tmp;
        }
 
        x++;
    }
 
    rep(j,0,col-1)
    {
        if(loc[j]==-1) continue;
        a[loc[j]][col]/=a[loc[j]][j];
        a[loc[j]][j]/=a[loc[j]][j];
    }
 
    return;
}
 
int n,m;
char gr[105][105];
void init()
{
	num=row=col=n*m;
	mem(a);
    //num=row=col=100;
    //mem(a);
    //memn(s);
    memn(loc);
}

int tn[405];

void slv()
{
	int i,j,k;
	sc3(n,m,ts);
	init();
	int st=-1;
	f(i,n*m)tn[i]=i;
	f(i,n)scanf(" %s",gr[i]);
	f(i,ts)
	{
		sc2(j,k);j--,k--;int q1=j*m+k;
		sc2(j,k);j--,k--;int q2=j*m+k;
		
		tn[q1]=q2;
		tn[q2]=q1;
	}
	f(i,n)
	{
		f(j,m)
		{
			if(gr[i][j]=='%')
			{
				a[i*m+j][i*m+j]=1.0;
				a[i*m+j][col]=-1.0;
				continue;
			}
			if(gr[i][j]=='#'||gr[i][j]=='*')
			{
				a[i*m+j][i*m+j]=1.0;
				continue;
			}
			if( gr[i][j]=='A' )st=i*m+j;
			
			a[i*m+j][i*m+j]=1.0;
			
			double cnt=0;
			f(k,4)
			{
				int x=i+dx[k];
				int y=j+dy[k];
				if( x<0||x>=n||y<0||y>=m|| gr[x][y]=='#' )continue;
				cnt+=1.0;
			}
			if(cnt<1)continue;
			cnt=1/cnt;
			f(k,4)
			{
				int x=i+dx[k];
				int y=j+dy[k];
				if( x<0||x>=n||y<0||y>=m|| gr[x][y]=='#' )continue;
				a[i*m+j][tn[x*m+y]]=-cnt;
			}
		}
	}
	assert(st!=-1);
	//cerr<<loc[st]<<endl;
	
	gauss();
	//cerr<<loc[st]<<endl;
	printf("%.10lf\n",-a[loc[st]][col]);
}
 
int main()
{
	
	slv();
	return 0;
    //S(ts);
    //while(ts--)
    //{
        //init();
 
        //int x;
 
        //S(n);
        //while(n--) S(x),S(s[x-1]),s[x-1]--;
 
        //rep(i,0,num-1)
        //{
            //if(s[i]==-1) s[i]=i;
            //a[i][i]=1.0;
        //}
 
        //rep(i,0,num-2)
        //{
            //double out=0.0;
            //rep(j,1,6)
            //{
                //if(i+j>=num) out+=1.0;
                //else a[i][s[i+j]] -= 1.0/6.0;
            //}
            //a[i][i] -= out/6.0;
 
            //a[i][col]=1.0;
        //}
 
        //gauss();
 
        //int pos=0;
 
		//printf("%.10lf\n",a[loc[pos]][col]);
    //}
 
	return 0;
}