#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) {
    // Return the minimum number of characters to make the password strong
    int count = 4;
    for (int i = 0; i < n; i++)
    {
        if (password[i] > 47 && password[i] < 58)
        {
            count--;
            break;
        }
    }
    for (int i = 0; i < n; i++)
    {
        if (password[i] > 64 && password[i] < 91)
        {
            count--;
            break;
        }
    }
    for (int i = 0; i < n; i++)
    {
        if (password[i] > 96 && password[i] < 123)
        {
            count--;
            break;
        }
    }
    for (int i = 0; i < n; i++)
    {
        if (password[i] > 32 && password[i] < 46)
        {
            count--;
            break;
        }
        else if (password == 64)
        {
            count--;
            break;
        }
    }
    if ((n + count) > 5)
        return count;
    else
        return (6 - n);
}

int main() {
    int n; 
    scanf("%i", &n);
    char* password = (char *)malloc(512000 * sizeof(char));
    scanf("%s", password);
    int answer = minimumNumber(n, password);
    printf("%d\n", answer);
    return 0;
}