#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <utility>
#include <map>
#include <set>
#include <queue>
#include <iomanip>
#include <cstring>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
typedef long long ll;
#define rep(i,n) for (int i = 0; i < int(n);i++)

int main(){
  ll l,r,c;
  cin >> l >> r >> c;
  ll ans = 1000;
  for (ll i = l; i <= min(l + 2000,r);i++){
    if ((i*c)%1000 == 0) {
      ans = 0;
      break;
    }
    ans = min(ans,1000-(i*c)%1000);
  }
  cout << ans << endl;
  

  return 0;
}