#include <iostream>
using namespace std;
 
int main()
{
    int ocenka;
    cin >> ocenka;
    
    int poeni;
    if(ocenka == 2) {
        poeni = 60;
    }
    else if(ocenka == 3) {
        poeni = 70;
    }
    else if(ocenka == 4) {
        poeni = 80;
    }
    else if(ocenka == 5) {
        poeni = 90;
    }
    
    int T1, T2, T3, T4;
    cin >> T1 >> T2 >> T3 >> T4;
    
    int zbir = T1 + T2 + T3 + T4;
    
    int T5 = poeni * 5 - zbir;
    
    if(T5 > 100) {
        cout << "GRESHKA" << endl;
    }
    else if(T5 < 0) {
        cout << 0 << endl;
    }
    else {
        cout << T5 << endl;
    }
    
    return 0;
}