nb, pb, jb = input().split()

if len(pa) > len(pb):
    print(na)
elif len(pa) < len(pb):
    print(nb)
else:
    pa = int(pa)
    pb = int(pb)
    if pa > pb:
        print(na)
    elif pa < pb:
        print(nb)
    else:
        print(-1)