def main():
    A, B, C, D = map(int, input().split())
    lot = 1 + C
    eatable_lot = D // lot
    vegi_count = 0
    for lot in range(1, eatable_lot + 1):
        capacity = max(D - lot, 0)
        if capacity <= 0:
            break
        vegi_count += 1
        A -= 1
        B -= C
        if A <= 0 or B <= 0:
            break
    print(vegi_count)

if __name__ == "__main__":
    main()