def main():
    L, R, C = map(int, input().split())
    minimum_change = 1000
    for liter in range(L, R+1):
        rest = C*liter % 1000
        if rest == 0:
            minimum_change = 0
        else:
            minimum_change = min(
                minimum_change,
                1000 - rest
            )
    print(minimum_change)


if __name__ == "__main__":
    main()