#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 small=1;
    int big=1;
    int charr=1;
    int digi=1;
    for(int i=0;i<n;i++){
        int temp=password[i];
        //printf("%d\n",temp);
        if(temp>=65 && temp<= 90){
            big=0;
           // printf("big\n");
            continue;
        }
        if( temp>=97 && temp<= 122){
            small=0;
            //printf("small\n");
            continue;
        }
        if(temp>=48 && temp<= 57){
            digi=0;
            //printf("digi\n");
            continue;
        }
            charr=0;
            //printf("charr\n");
        
    }
    int no=small+big+charr+digi;
    if (no+n<6){
        return 6-n;
    }
    return no;
}

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;
}