#include <bits/stdc++.h>

using namespace std;
void fast_io() {
    ios::sync_with_stdio(false);
    std::cin.tie(nullptr);
}

int main() {
    fast_io();
    int l, r, c;
    cin >> l >> r >> c;
    vector<bool> vis(1000, false);
    for (long long x = l; x <= r; x++) {
        long long ch = 1000 - (x * c) % 1000;
        if (ch == 1000) ch = 0;
        if (vis[ch]) {
            break;
        }
        vis[ch] = true;
    }
    for (int i = 0; i < 1000; i++) {
        if (vis[i]) {
            cout << i << endl;
            return 0;
        }
    }
}