L,R,C = map(int,input().split())

ans = 1000
s = set()
for i in range(L,R + 1):
    t = i * C % 1000
    if t != 0:
        t = 1000 - t
    if t < ans:
        ans = t
    if t in s:break
    s.add(t)
print(ans)