#include <bits/stdc++.h>
using namespace std;
using lint = long long;
#define rep(i, s, n) for (int i = (s); i < (int)(n); i++)
#define Yes cout << "Yes" << endl
#define No cout << "No" << endl
int main() {
    lint l,r,c,b,ans=999;
    cin >> l >> r >> c;
    rep(i,l,r+1) {
        if((i*c)%1000==0) {
            ans=0;
        } else {
            b = 1000 - ((i*c)%1000);
            ans=min(ans,b);
        }
    }
    cout << ans << endl;
}