#include <bits/stdc++.h>

using namespace std;

string numbers = "0123456789";
string lower_case = "abcdefghijklmnopqrstuvwxyz";
string upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
string sc = "!@#$%^&*()-+";
    
int minimumNumber(int n, string p) {
    // Return the minimum number of characters to make the password strong
    int m[4]={},sm=0,i,j;
    for(i=0;i<n;i++){
        if(p[i]>=65&&p[i]<=90)m[1]=1;
        if(p[i]>=97&&p[i]<=122)m[2]=1;
        if(p[i]>=48&&p[i]<=57)m[0]=1;
        for(j=0;j<12;j++)if(p[i]==sc[j])m[3]=1;
    }
    for(i=0;i<4;i++)sm+=m[i];
    int rem = 4-sm;
    //n+=rem;
    //return ((n>=6)?0:(6-n));
    
    if(sm==4&&n>=6)return 0;
    if(n>=6&&sm<4)return 4-sm;
    if(sm==4&&n<6)return 6-n;
    if(sm<4&&n<6){
        rem=(4-sm);
        if(n+rem>=6)return rem;
        else return (6-(n));
        //return ();
    }
    return 0;
    //return ()
}

int main() {
    int n;
    cin >> n;
    string password;
    cin >> password;
    int answer = minimumNumber(n, password);
    cout << answer << endl;
    return 0;
}