//moshasu

#include <iostream>
#include <vector>
#include <cmath>
#include <map>
#include <set>
#include <iomanip>
#include <queue>
#include <algorithm>
#include <numeric>
#include <deque>
#include <complex>
#include <cassert>

using namespace std;
using ll = long long;

int main(){

    ll L, R, C, ans=1e18, mi;
    cin >> L >> R >> C;
    mi = min(R, L+1000);
    for (ll i=L; i<=mi; i++) ans = min(ans, (i*C+999)/1000 * 1000 - i*C);

    cout << ans << endl;

    return 0;
}