#include <bits/stdc++.h>

using namespace std;

int minimumNumber(int n, string p) {
    int x[5]={0};
    // Return the minimum number of characters to make the password strong
    for(int i=0;i<n;i++){
        if(p[i]>=65&&p[i]<=90)
            x[0]=1;
        if(p[i]>=97&&p[i]<=122)
            x[1]=1;
        if(p[i]>=48&&p[i]<=57)
            x[2]=1;
        if(p[i]=='!'||p[i]=='@'||p[i]=='#'||p[i]=='$'||p[i]=='%'||p[i]=='^'||p[i]=='&'||p[i]=='*'||p[i]=='('||p[i]==')'||p[i]=='-'||p[i]=='+')
            x[3]=1;
    }
    if(n>=6)x[4]=1;
    int ans=0;
    for(int i=0;i<4;i++){
        if(x[i]==0)
            ans++;
    }
    return max(ans,6-n);
}

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