def main():
    a, b, c, d = [int(x) for x in input().split(" ")]
    max_veg = 0
    i = 0
    while i <= a:
        sum = i + c * i
        if sum <= d and c * i < b:

            max_veg = i
        i += 1
    print(max_veg)



if __name__ == "__main__":
    main()