#include <bits/stdc++.h>

using namespace std;

int minimumNumber(int n, string a) {
    // Return the minimum number of characters to make the password strong
     
    int na,l,u,s;
    na=l=s=u=0;
    for(int i=0;i<n;i++){
        if(a[i]>='0' && a[i]<='9') na++;
        else if(a[i]>='a' && a[i]<='z') l++;
        else if(a[i]>='A' && a[i]<='Z') u++;
        else if(a[i]=='!' || a[i]=='@' ||a[i]=='#' ||a[i]=='$' ||a[i]=='%' ||a[i]=='^' ||a[i]=='&' ||a[i]=='*' ||a[i]=='(' ||a[i]==')'          ||a[i]=='-' ||a[i]=='+') s++;
    }
    int ans=0;
    ans+=(na==0?1:0);
    ans+=(l==0?1:0);
    ans+=(u==0?1:0);
    ans+=(s==0?1:0);
    if(ans+n<6) return 6-n;
    return ans;
}

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