#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#include<bits/stdc++.h>
#include<atcoder/all>
using namespace std;
using namespace atcoder;
using ll=long long;

void IO(){
  ios::sync_with_stdio(false);
  std::cin.tie(nullptr);
}

int main(){
  IO();
  ll l,r,c;
  cin>>l>>r>>c;
  if((r-l+1)>=1000){
    cout<<0<<endl;
    exit(0);
  }
  ll ans=1e18;
  for(ll i=l;i<=r;i++){
    ll num=i*c;
    ll tmp=(num+1000-1)/1000;
    ans=min(ans,1000*tmp-num);
  }
  cout<<ans<<endl;
}