L,R,C = map(int, input().split())
used = [0]*1001
ans = 0
for x in range(L,R+1):
    d = C*x % 1000
    if d == 0:
        d = 1000
    if not used[d]:
        ans = max(ans, d)
        used[d] = 1
    else:
        break
print(1000-ans)