#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (ll i = 0; i < (n); ++i)
#define bitrep(i, n) for (ll i = 0; i < (1 << n); ++i)
#define all(a) (a).begin(), (a).end()
#define rall(a) (a).rbegin(), (a).rend()
#define yesNo(b) ((b) ? "Yes" : "No")
using ll = long long;
using ull = unsigned long long;
string alphabet = "abcdefghijklmnopqrstuvwxyz";
string ALPHABET = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
const double pi = 3.141592653589793;
int smallMOD = 998244353;
int bigMOD = 1000000007;

int main()
{
    int l, r, x;
    cin >> l >> r >> x;
    x %= 1000;
    int ans = INT32_MAX;
    rep(i, min(r - l + 1, 1000))
    {
        ans = min(ans, abs(1000 - int(((i + l) % 1000) * x)) % 1000);
    }
    cout << ans << endl;
    return 0;
}