#include <bits/stdc++.h>

using namespace std;

int minimumNumber(int n, string s) {
    int i;
    int sum1=0;
        if(n<6){
           sum1= 6-n;
        }
    
        int uc=0,lc=0,sc=0,nc=0;
        for(i=0;i<n;i++){
            if(s[i]>64&&s[i]<91)
                uc=1;
            if(s[i]>96&&s[i]<123)
                lc=1;
           if(s[i]=='!'||s[i]=='@'||s[i]=='#'||s[i]=='$'||s[i]=='%'||s[i]=='^'||s[i]=='&'||s[i]=='*'||s[i]=='('||s[i]==')'||s[i]=='-'||s[i]=='+')
               sc=1;
            if(s[i]>47&&s[i]<58)
                nc=1;
        }
        int sum2=4-uc-sc-lc-nc;
        
    
    if(sum1>sum2)
        return sum1;
    else
        return sum2;
}

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