#include<iostream>
#include<algorithm>
using namespace std;

int main() {
    long long l, r, c;
    cin >> l >> r >> c;
    long long res = 1000;
    for (long long i = l; i <= r; i++) {
        res = min(res, 1000 - ((i * c) % 1000));
        if (i * c % 1000 == 0) res = 0;
    }
    cout << res << endl;
}