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


int main() {
    int n;
    cin >> n;
    string s;
    cin >> s;
    bool c[4];
    for(int i=0;i<4;i++){
        c[i]=0;
    }
    for(int i=0;i<s.length();i++){
        if(s[i]>=48&&s[i]<=57) c[0]=1;
        if(s[i]>=65&&s[i]<=91) c[1]=1;
        if(s[i]>=97&&s[i]<=122) c[2]=1;
        if(s[i]=='!'||s[i]=='@'||s[i]=='#'||s[i]=='$'||s[i]=='%'||s[i]=='^'||s[i]=='&'||s[i]=='*'||s[i]=='('||s[i]==')'||s[i]=='-'||s[i]=='+') c[3]=1;
    }
    if(s.length()<6){
        if(c[0]+c[1]+c[2]+c[3]==4){
            cout << 6-s.length() << endl;
        }else{
            int p = 4-(c[0]+c[1]+c[2]+c[3])>6-s.length()?4-(c[0]+c[1]+c[2]+c[3]):6-s.length();
            cout << p << endl;
        }
    }else{
        cout << 4-(c[0]+c[1]+c[2]+c[3]) << endl;
    }
    return 0;
}