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