def main():
    i = input()
    lst = i.split(' ')
    A, B, C, D = int(lst[0]), int(lst[1]), int(lst[2]), int(lst[3])
    count = 0
    while A >= 1 and B >= C and D >= C+1:
        A -= 1
        B -= C
        D -= C + 1
        count += 1
        # print('A: {}, B: {}, D: {}'.format(A, B, D))
    print(count)


if __name__ == '__main__':
    main()