#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 i;
    int special_char = 0;
    int digits = 0;
    int caps = 0;
    int lowercase = 0;
    int sum=0;
    int char_reqd = 0;
    for(i=0;i<n;i++){
        if (password[i] == '!' || password[i] == '@' || password[i] == '#' || password[i] == '$' || password[i] == '%' || password[i] == '^' || password[i] == '&' || password[i] == '*' || password[i] == '(' || password[i] == ')' || password[i] == '-' || password[i] == '+'){special_char=1;}
        
        if (password[i]=='a' || password[i]=='b' ||password[i]=='c' || password[i]=='d' ||password[i]=='e' || password[i]=='f' ||password[i]=='g' || password[i]=='h' ||password[i]=='i' || password[i]=='o' ||password[i]=='n' || password[i]=='l' ||password[i]=='k' || password[i]=='j' ||password[i]=='p' || password[i]=='q' ||password[i]=='r' || password[i]=='s' ||password[i]=='t' || password[i]=='u' ||password[i]=='m' || password[i]=='v' ||password[i]=='w' || password[i]=='x' || password[i]=='z' ||password[i]=='y' ){lowercase=1;}
    
    if(password[i]=='A' || password[i]=='B' ||password[i]=='C' || password[i]=='D' ||password[i]=='E' || password[i]=='F' ||password[i]=='G' || password[i]=='H' ||password[i]=='I' || password[i]=='O' ||password[i]=='N' || password[i]=='L' ||password[i]=='K' || password[i]=='J' ||password[i]=='P' || password[i]=='Q' ||password[i]=='R' || password[i]=='S' ||password[i]=='T' || password[i]=='U' ||password[i]=='M' || password[i]=='V' ||password[i]=='W' || password[i]=='X' || password[i]=='Z' ||password[i]=='Y' ){caps=1;}
if (password[i]=='1' || password[i]=='2' ||password[i]=='3' || password[i]=='4' ||password[i]=='5' || password[i]=='0' ||password[i]=='9' || password[i]=='8' ||password[i]=='7' || password[i]=='6'){digits =1;}
    }

sum = special_char + digits + caps + lowercase;
char_reqd = 4-sum;
if ((n+char_reqd)<6){
    char_reqd = char_reqd + (6-(n+char_reqd));
}
return char_reqd;
}

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