import sys
sys.setrecursionlimit(5*10**5)
input = sys.stdin.readline
from collections import defaultdict, deque, Counter
from heapq import heappop, heappush
from bisect import bisect_left, bisect_right
from math import gcd

l,r,c = map(int,input().split())

ans = float("inf")
for i in range(l, min(r, l+1000)+1):
    if c * i % 1000 == 0:
        print(0)
        break
    tmp = 1000 - c * i % 1000
    ans = min(ans, tmp)
else:
    print(ans)