#include<bits/stdc++.h>usingnamespace std;intmain(){int a, b, c, res =0;
cin >> a >> b >> c;if(a <=80)
res = a;elseif(b <=40)
res = a + b;else
res = a + b + c;if(res >=250)
cout <<1;elseif(res >=220)
cout <<2;elseif(res >=175)
cout <<3;else
cout <<-1;return0;}