#include <bits/stdc++.h>
#include<stdio.h>
using namespace std;
int main(){
	int n;
	cin >>n;
	string s;
	cin >> s;
	int d=0, l=0, u=0, sp=0;
	
	for(int i=0;i<s.length();i++){
		int x= s[i]+0;
		if(x>=97 && x<=122) l=1;
		else if(x>=65 && x<=90) u=1;
		else if(x>=48 && x<=57) d=1;
		else sp=1;
	}
	int sl=s.length();
	int need= 4- (d+u+l+sp);
	//cout << need << endl;
	if(sl >=6 && need==0) cout << "0";
	else if(sl >= 6 && need>0) cout << need;
	else if(sl <=6 && need==0) cout << 6-sl;
	else {
		sl= sl+need;
		if(sl>=6) cout << need;
		else cout << need+ (6-sl);
	}
	return 0;
}