#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;
}