#!/usr/bin/env python3
#fileencoding: utf-8

Sa, Pa, Xa = [int(v) if i == 1 else v for i, v in enumerate(input().strip().split(" "))]
Sb, Pb, Xb = [int(v) if i == 1 else v for i, v in enumerate(input().strip().split(" "))]

if Pa > Pb:
    print(Sa)
elif Pa < Pb:
    print(Sb)
else:
    print(-1)