#include <math.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <assert.h>
#include <limits.h>
#include <stdbool.h>

int minimumNumber(int n, char* password) {
    int i;
    int minAdd = 4;
    int upper = 0, lower = 0, digit = 0, spl = 0;
    
    for(i = 0; i < n; i++) {
        if(upper == 0) {
            if(password[i] >= 'A' && password[i] <= 'Z') {
                upper = 1;
                minAdd -= 1;
            }
        }
        if(lower == 0) {
            if(password[i] >= 'a' && password[i] <= 'z') {
                lower = 1;
                minAdd -= 1;
            }
        }
        if(digit == 0) {
            if(password[i] >= '0' && password[i] <= '9') {
                digit = 1;
                minAdd -= 1;
            }
        }
        if(spl == 0) {
            switch(password[i]) {
                case '!':
                case '@':
                case '#':
                case '$':
                case '%':
                case '^':
                case '&':
                case '*':
                case '(':
                case ')':
                case '-':
                case '+':
                    spl = 1;
                    minAdd -= 1;
            }
        }
    }
    if(n + minAdd < 6) {
        return 6 - n;
    }
    
    return minAdd;
}

int main() {
    int n; 
    scanf("%i", &n);
    char* password = (char *)malloc(128 * sizeof(char));
    scanf("%s", password);
    int answer = minimumNumber(n, password);
    printf("%d\n", answer);
    return 0;
}