#include<stdio.h>
int main()
{
    int i,n,z,y,sum=0,count;
    int lower=0,upper=0,special=0,digit=0;
    char str[100];
    scanf("%d",&n);
    scanf("%s",str);    
    for(i=0;i<n;i++)
    {
        if(str[i]>='a' && str[i]<='z')
            lower=1;
        else if(str[i]>='A' && str[i]<='Z')
            upper=1;
        else if(str[i]>='0' && str[i]<='9')
            digit=1;
        else
            special=1;            
    }
    z=4-(lower+special+upper+digit);
    if((z+n)>=6)
        printf("%d\n",z);
    else
    printf("%d\n",6-n);
    return 0;
}