#include<bits/stdc++.h>
using namespace std;

int main()
{
	int n; cin>>n;
    string s; cin>>s;
    
    int t1=0, t2=0, t3=0, t4=0;
    for(int i=0; i<n; i++)
    {
        if(s[i]>='0' && s[i]<='9') t1++;
        if(s[i]>='a' && s[i]<='z') t2++;
        if(s[i]>='A' && s[i]<='Z') t3++;
        if(s[i]=='!' || s[i]=='@' || s[i]=='#' || s[i]=='%' || s[i]=='^' || s[i]=='&' || s[i]=='*' || s[i]=='(' ||                      s[i]==')' || s[i]=='-' || s[i]=='+') t4++;
    }
    
    if(t1>0) t1=1;
    if(t2>0) t2=1;
    if(t3>0) t3=1;
    if(t4>0) t4=1;
    
    if(n>=6) cout<<4-(t1+t2+t3+t4);
    if(n<6)
    {
        int x = t1+t2+t3+t4;
        int add = 4-x;
        int extra = 0;
        if(add+n<=6) extra = 6-(add+n);
        cout<<add+extra;
    }

	return 0;
}