def main():
    a, b, c, d = map(int, input().split(' '))

    vege = 0
    meat = 0
    s = d
    while  vege < a and meat < b and s - (vege + meat + 1 + c) >= 0:
        vege += 1
        meat = c * vege
    print(vege)

if __name__ =='__main__':
    main()