x, y = map(int, input().split())
x2, y2 = map(int, input().split())
if x != y:
    print(max(x, y))
else:
    if x2 != y2:
        print(x)
    elif x * x2 > 0 and y * y2 > 0:
        print(x + 1)
    else:
        print(x)