#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
  #include "settings/debug.cpp"
  #define _GLIBCXX_DEBUG
#else
  #define Debug(...) void(0)
#endif
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

int main() {
  ll l, r, c;
  cin >> l >> r >> c;
  ll ans = 1e18;
  for (int x = l; x <= min(l + 1000, r); x++) {
    ll price = x * c;
    ans = min(ans, (1000 - price % 1000) % 1000);
  }
  cout << ans << endl;
  return 0;
}