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


int main() {
    int n; 
    scanf("%i", &n);
    char* password = (char *)malloc(512000 * sizeof(char));
    scanf("%s", password);
    int answer = 0;
    int i;
    i = 0;
    int uc;
    int lc;
    int sc;
    int d;
    uc =0;
    lc = 0;
    sc = 0;
    d = 0;
    while(i < n)
    {
        if (uc == 0 && password[i] >= 'A' && password[i] <= 'Z')
            uc = 1;
        if (lc == 0 && password[i] >= 'a' && password[i] <= 'z')
            lc = 1;
        if (sc == 0 && ((password[i] >= '!' && password[i] <= '/') || (password[i]>'z' && password[i]<='~')))
            sc = 1;
        if (d == 0 && password[i] >= '0' && password[i] <= '9')
            d = 1;
        i++;
    }
    answer = 4 - uc -lc -sc -d;
    if (answer < 6 - n)
        answer = 6 - n;
    printf("%d\n", answer);
    return 0;
}