#include <bits/stdc++.h>
using namespace std;
int main(){
  int L, R, C;
  cin >> L >> R >> C;
  if (R - L >= 2000){
    cout << 0 << endl;
  } else {
    int ans = 1000;
    for (int i = L; i <= R; i++){
      ans = min(ans, (int) (1000 - (long long) i * C % 1000) % 1000);
    }
    cout << ans << endl;
  }
}