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

    veg = 0
    meat = 0
    cap = 0

    for i in range(1, A + 1):
        veg += 1
        meat += C
        cap = veg + meat
        if meat > B or cap > D:
            print(veg - 1)
            return
    print(veg)
    

if __name__ == '__main__':
    main()