#include <bits/stdc++.h>
using namespace std;
int main() {
  long long l, r, c;
  cin >> l >> r >> c;
  long long ans = 1000;
  for (long long x = l; x <= min(l + 1000, r); x++) {
    long long now = (x * c) % 1000;
    if (now != 0) now = 1000 - now;
    ans = min(ans, now);
  }
  cout << ans << endl;
  return 0;
}