#include <bits/stdc++.h>
#include<iostream>
#include<map>
#include<vector>
#include <algorithm>
#include<math.h>
#include <iomanip>
#include<set>
#include <numeric>
#include<string>
using ll = long long;
using namespace std;


int main()
{
    ll l, r, c, rest = 0, min1 = 1001;
    cin >> l >> r >> c;
    set<ll> st;
    for (ll i = l; i <= r; i++){
        rest = 1000 - i*c%1000;
        if (rest == 1000){
            cout << 0 << endl;
            return 0;
        }
        min1 = min(min1, rest);
        if (!st.count(rest)) st.insert(rest);
        else {
            cout << min1 << endl;
            return 0;
        }
    }
    cout << min1 << endl;
}