l, r, c = map(int, input().split())
if r - l > 10000:
    print(0)
else:
    ans = float("inf")
    for i in range(l, r + 1):
        if c * i % 1000 == 0:
            ans = 0
        else:
            ans = min(ans, 1000 - (c * i) % 1000)
    print(ans)