// 提出時にassertはオフ
#ifndef DEBUG
#ifndef NDEBUG
#define NDEBUG
#endif
#endif

#include <bits/stdc++.h>
using namespace std;
using ll = long long;

#define ALL(x) (x).begin(), (x).end()
template <class T> using vec = vector<T>;

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    ll L, R, C;
    cin >> L >> R >> C;
    if(R - L >= 1000) {
        cout << 0 << "\n";
        return 0;
    }
    ll ans = 1000;
    for(ll x = L; x <= R; x++) {
        ans = min(ans, ((x * C + 999) / 1000) * 1000 - x * C);
    }
    cout << ans << "\n";
}