#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
int main()
{
    ll L,R,C;
    cin>>L>>R>>C;
    ll cnt;
    ll m=INT_MAX;
    for(ll i=L;i<=R;i++)
    {
        cnt=1000-(i*C)%1000;
        if(cnt<m)
        m=cnt;
    }
    cout<<m<<endl;
    return 0;
}