#include <bits/stdc++.h>

using namespace std;

int minimumNumber(int n, string password) {
    
    int capf = 0;
    int smlf = 0;
    int sppf = 0;
    int numf = 0;
    for( int i = 0 ; i < n ; i++)
    {
        if(capf != 1){
            if(password[i] >= 65 && password[i] <= 90)
               capf = 1;
        }
        if(smlf != 1){
            if(password[i] >= 97 && password[i] <= 122)
               smlf = 1;
        }
        if(numf != 1){
            if(password[i] >= 48 && password[i] <= 57)
               numf = 1;
        }
        if(sppf != 1){
            if(password[i] == '!' || password[i] == '@' || password[i] == '#' || password[i] == '$' || password[i] == '%' || password[i] == '^' || password[i] == '&' || password[i] == '*' || password[i] == '(' || password[i] == ')' || password[i] == '-' || password[i] == '+')
               sppf = 1;
        }
        if(capf == 1 && smlf == 1 && numf == 1 && sppf == 1)    break;
    }
    if( n > 3 )
    {
        int count = 0;
        if(capf!=1) count++;
        if(smlf!=1) count++;
        if(numf!=1) count++;
        if(sppf!=1) count++;
        if(count+n < 6) return 6-n;
        return count;
    }
    else 
        return 6-n;
    // Return the minimum number of characters to make the password strong
}

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