#include <math.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <assert.h>
#include <limits.h>
#include <stdbool.h>
int uc=0,lc=0,d=0,c=0;
int minimumNumber(int n, char* password) {
    int ans=0;
    for(int i=0;i<n;i++)
    {
        if (password[i]>=48 && password[i]<=57)
            d++;
        else if(password[i]<=90 && password[i]>=65)
            uc++;
        else if(password[i]<=122 && password[i]>=97)
            lc++;
        else
            c++;
    }
    if(d==0)
        ans++;
    if(uc==0)
        ans++;
    if(lc==0)
        ans++;
    if(c==0)
      ans++;
    
    if((ans+n)>=6)
        return ans;
    else
        return(ans+(6-(n+ans)));
    // Return the minimum number of characters to make the password strong
}

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;
}