#include <bits/stdc++.h>

using namespace std;

const int INF = 1e9;
using ll = long long;
using inv = vector<int>;
using stv = vector<string>;
using pint = pair<int,int>;
#define FOR(i,l,r) for(int i=(l); i<(r); i++)
#define rep(i,r) for(int i=0; i<(r); i++)
#define repl(i,r) for(long long i=0; i<(r); i++)
#define FORl(i,l,r) for(long long i=(l); i<(r); i++)
#define INFL ((1LL<<62)-(1LL<<31))
#define pb(x) push_back(x)
#define CIN(x) cin >> x



int main(){
  ll L,R,C;
  cin >> L >> R >> C;
  
  const ll MOD = 1000;
  ll minC = L*C;
  ll maxC = R*C;
  
  ll ans = INFL;
  
  FORl(i,L,R+1){
    ll num = C*i;
    ll mi = 0;
    if(num % MOD == 0) mi = 1000;
    else mi = num % MOD;
    
    ans = min(ans, 1000-mi);
  }
  cout << ans << endl;
}