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

#ifdef _RUTHEN
#include <debug.hpp>
#else
#define show(...) true
#endif

using ll = long long;
#define rep(i, n) for (int i = 0; i < (n); i++)
template <class T> using V = vector<T>;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    long long L, R, C;
    cin >> L >> R >> C;
    long long ans = 1LL << 60;
    for (long long x = L; x <= min(L + 1000000, R); x++) {
        if (C * x % 1000 == 0) {
            ans = 0;
        } else {
            ans = min(ans, 1000 - C * x % 1000);
        }
    }
    cout << ans << '\n';
    return 0;
}