#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 ans = INFL;
    
    FORl(i,L,1e8){
      if(i > R) break;  
      ll num = (1000LL -((i*C)%MOD)+MOD)%MOD;
//        cout << num << endl;
        
        ans = min(ans, num);
    }
    cout << ans << endl;
}