#include <bits/stdc++.h>

using namespace std;

int minimumNumber(int n, string p) {
    
    int i,j; int c1=0,c2=0,c3=0,c4=0;
    for(i=0;i<n;i++){
        
        
     if(p[i]>=97 && p[i]<=122){ c1++;}  
      if(p[i]>=65 && p[i]<=90){ c2++;}
        if(p[i]>=48 && p[i]<=57){c3++;}
        if(p[i]==33  ||  p[i]==40 ||  p[i]==41   ||  p[i]==33  ||  p[i]==64  ||  p[i]==36  ||  p[i]==33  ||  p[i]==35  ||  p[i]==37  ||  p[i]==38  ||  p[i]==43  ||  p[i]==45   ){ c4++; }
    }
    int count=0;
    if(c1==0){count++; }
    if(c2==0){count++; }
    if(c3==0){count++; }
    if(c4==0){count++; }
    
    int x=6-n;
    return max(x,count);
    
    
}

int main() {
    int n;
    cin >> n;
    string password;
    cin >> password;
    int answer = minimumNumber(n, password);
    cout << answer << endl;
    return 0;
}