#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* p) {
  int i,j,k=0,lp=0,up=0,l,num=0,a,b,c;
    for(i=0;i<n;i++)
    {
        l=p[i];
      if(p[i]=='!' || p[i]=='@' || p[i]=='#' || p[i]=='$' || p[i]=='%'|| p[i]=='^'||p[i]=='&'||p[i]=='*'||p[i]=='('|| p[i]==')'||p[i]=='-'||p[i]=='+')
          k=1;
        if(l>=65 && l<=90 )
            up=1;
        if(l>=97 && l<=122)
            lp=1;
        if(l>=48 && l<=57)
            num=1;
     }
  c=4-(up+lp+k+num);
  //  printf("%d%d %d %d",k,up,lp,num);
 if(n<6)
 {
    if(c!=4 && c<(6-n))
        a=6-n;
     if(c!=4 && c>=(6-n))
        a=c;
     if(c==4)
         a=6-n;
     
 }
    else
        a=c;
    return a;
}

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;
}