#include<bits/stdc++.h>
using namespace std;
#define MOD 1000000007
typedef long long ll;
ll power(ll a,ll b){
    if(a==1||b==0)  return 1;
    ll temp = power(a,b/2)%MOD;
    if(b%2==0)
    return (temp*temp)%MOD;
    return (a*((temp*temp)%MOD))%MOD;
}
int main()
{
    int n;
    string s;
    cin>>n>>s;
    int dig=0,low=0,high=0,dif=0,cn=0;
    for(int i=0;i<n;i++){
        if((s[i]-'0')>=0&&(s[i]-'0')<10)
        dig++;
        if((s[i]-'a')>=0&&(s[i]-'a')<26)
        low++;
        if((s[i]-'A')>=0&&(s[i]-'A')<26)
        high++;
        if((s[i]-'!'==0)||(s[i]-'@'==0)||(s[i]-'#'==0)||(s[i]-'$'==0)||(s[i]-'%')==0||(s[i]-'^')==0||(s[i]-'&')==0||
        (s[i]-'*')==0||(s[i]-'(')==0||(s[i]-')')==0||(s[i]-'-')==0||(s[i]-'+')==0)
        dif++;
    }
    if(dig==0)
    cn++;
    if(low==0)
    cn++;
    if(high==0)
    cn++;
    if(dif==0)
    cn++;
    cout<<max(cn,6-n)<<"\n";
    return 0;
}