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

int max(int  a,int b){
    return (a>b)?a:b;
}

int main() {
    int n;
    cin>>n;
    string s;
    cin>>s;
    bool isLower = false;
    bool isUpper = false;
    bool isNumber = false;
    bool isSpecial = false;
    
    for(int i=0;i<n;i++){
        if(s[i]>='a'&&s[i]<='z') isLower = true;
        else if(s[i]>='A' && s[i]<='Z') isUpper = true;
        else if(s[i]>='0' && s[i]<='9') isNumber = true;
        else isSpecial = true;
    }
    
    int count = 0;
    
    if(!isLower) count++;
    if(!isUpper) count++;
    if(!isNumber) count++;
    if(!isSpecial) count++;
    
    if(n>6) cout<<count;
    else cout<<max(count,(6-n));
    return 0;
}