def main():
    A, B, C, D = map(int, input().split())

    for n in range(1, A + 1):
        veg = n
        meat = n * C
        if veg + meat >= D:
            print(veg - 1)
            return
        elif A + A * C <= D and B / C >= A:
            print(A)
            return
        elif B / C <= A:
            print(B // C)
            return

if __name__ == '__main__':
    main()