#include <math.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <assert.h>
#include <limits.h>
#include <stdbool.h>
#include<ctype.h>

int minimumNumber(int n, char* pwd) {
    // Return the minimum number of characters to make the password strong
    int dig=0,i=0,lw=0,up=0,spl=0,len=strlen(pwd),extra=0,nl=0;
    for(i=0;i<len;i++)
    {
        if(isdigit(pwd[i])) dig++;
        else if(islower(pwd[i])) lw++;
        else if(isupper(pwd[i])) up++;
        else spl++;
    } 
    
    if(len<6)
    {
        if(len==5)
        {
            if(!dig) extra++;
            if(!lw)  extra++;
            if(!up)  extra++;
            if(!spl) extra++;
            nl=len+extra;
            if(nl>=6) return extra;
            else return 1;
        }
       else  if(len==4)
        {
            if(!dig) extra++;
            if(!lw)  extra++;
            if(!up)  extra++;
            if(!spl) extra++;
            nl=len+extra;
            if(nl>=6) return extra;
            else return 2;
        } 
        else  if(len==3)
        {
            if(!dig) extra++;
            if(!lw)  extra++;
            if(!up)  extra++;
            if(!spl) extra++;
            nl=len+extra;
            if(nl>=6) return extra;
            else return 3;
        } 
        else  if(len==2)
        {
            if(!dig) extra++;
            if(!lw)  extra++;
            if(!up)  extra++;
            if(!spl) extra++;
            nl=len+extra;
            if(nl>=6) return extra;
            else return 4;
        } 
       else return (6-len);
    }
    else
    {
       
       
            if(!dig) extra++;
            if(!lw)  extra++;
            if(!up)  extra++;
            if(!spl) extra++;
           return extra;
        } 
    }
    


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;
}