#include <bits/stdc++.h>
using namespace std;
#define int long long
signed main(){
  int l,r,x;
  cin>>l>>r>>x;
  r = min(r,l+10000);
  int ans = 1e18;
  for(int i=l;i<=r;i++) ans = min(ans,1000-(x*i)%1000-1000*((x*i)%1000 == 0));
  cout<<ans<<endl;
}