#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */  
    int n;
    cin>>n;
    string s;
    cin>>s;
    int lc=0,uc=0,nc=0,sc=0;
    int i=0;
    while(i<n){
        if(s[i]>='a' && s[i]<='z')lc++;
        else if(s[i]>='A' && s[i]<='Z')uc++;
        else if(s[i]>='0' && s[i]<='9')nc++;
        else sc++;
        
        i++;
    }
    int ans=0;
    if(lc==0)ans++;
    if(uc==0)ans++;
    if(sc==0)ans++;
    if(nc==0)ans++;
    
    cout<<max(6-n,ans)<<endl;
    
    return 0;
}