a, b, n, m = map(int, input().split())
if a > b:
    c = a-b
    if (c//(n+1)) >= 0:
        print(b+(c//(n+1)))
    else:
        print(min(a, b))
if a < b:
    c = b-a
    if (c//(m+1)) >= 0:
        print(a+(c//(m+1)))
    else:
        print(min(a, b))
if a == b:
    print(min(a, b))