#ifdef LOCAL
#include <local.hpp>
#else
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,popcnt,lzcnt,abm,bmi,bmi2")
#include <bits/stdc++.h>
#define debug(...) ((void)0)
#define postprocess(...) ((void)0)
#endif

using namespace std;
using ll = long long;
using ld = long double;

void solve([[maybe_unused]] int test) {
    ll L, R, C;
    cin >> L >> R >> C;

    ll ans = numeric_limits<ll>::max();

    for (ll x = L; x <= min(L + 1000, R); x++) {
        ans = min(ans, 1000 - ((x * C) % 1000));
        if ((x * C) % 1000 == 0) {
            ans = 0;
        }
    }

    cout << ans << endl;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int t = 1;
    // cin >> t;
    for (int i = 1; i <= t; i++) {
        solve(i);
    }

    postprocess();
}