#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, add = 0, spare = 0, isupper = 0, islower = 0, isspecial = 0, isdigit = 0;
    for(i = 0;i < n; i++)
    {
        
        if(*(password + i) >= 65 && *(password + i) <= 90)
        {
            isupper = 1;
        }
        else if(*(password + i) >= 97 && *(password + i) <= 122)
        {
            islower = 1;
        }
         else if(*(password + i) >= 48 && *(password + i) <= 57)
        {
            isdigit = 1;
        }
         else 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) =='+')
        {
            isspecial = 1;
        }
    }
     if((strlen(password)) < 6)
        {
            add = 6 - n;
        }
    if(islower == 0)
    {
        spare += 1;
        //  printf("lower\n");
    }
    if(isupper == 0)
    {
        spare += 1;
         // printf("upper\n");
    }
    if(isdigit == 0)
    {
        spare += 1;
          //printf("isdigit\n");
    }
    if(isspecial == 0)
    {
        spare += 1;
          //printf("isspecial\n");
    }
    
    if(spare <= add)
    return add;
        return spare;
}

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;
}