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

void fast_io() {
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
}

int main(void) {
    fast_io();
    ll l, r, c;
    cin >> l >> r >> c;
    set<ll> st;
    for (ll i = l; i <= r; i++) {
        ll k = 1000 - i * c;
        k = (k + 1000) % 1000;
        if (st.count(k)) {
            cout << *st.begin() << endl;
            return 0;
        } else {
            st.insert(k);
        }
    }
    cout << *st.begin() << endl;
    return 0;
}