#include <bits/stdc++.h>
using ll = long long;
#define MOD 1000000007
#define Mod 998244353
const int MAX = 1000000005;
const long long INF = 1000000000000000005LL;
using namespace std;



int main() {
    ios::sync_with_stdio(0);cin.tie();
    ll L, R, C;
    cin >> L >> R >> C;
    ll ans = MAX;
    for (int x = L; x <= min(L+1005, R); x++) {
        if (x%1000*C%1000 == 0) ans = 0;
        else ans = min(ans, 1000 - x%1000*C%1000);
    }
    cout << ans << endl;
}