#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
int main() {
    ll l, r, c; cin >> l >> r >> c;
    ll min_change = 999;
    for(ll x = l; x <= r; x++){
        ll change = 1000-x*c%1000;
        if(change == 1000)change =0;
        if(min_change > change){
            min_change = change;
        }
    }
    cout << min_change << endl;
    return 0;
}