def main():
    A, B, C, D = map(int, input().split(" "))
    if A*C <= B and A + B <= D:
        print(A)
    elif A*C <= B and A + A*C > D:
        Aa = D // (1 + C)   
        print(Aa)
    elif A*C > B and B + B // C <= D:
        Ab = B // C  
        print(Ab)
    else:
        print(D // 1 + C)


if __name__ == "__main__":
    main()