na, pa, ja = input().split()
nb, pb, jb = input().split()

ans = -1

if len(pa) > len(pb):
    ans = pa
elif len(pa) < len(pb):
    ans = pb
else:
    for i in range(len(pa)):
        if int(pa[i]) > int(pb[i]):
            ans = pa
            break
        elif int(pa[i]) < int(pb[i]):
            ans = pb
            break

print(ans)