#include<iostream>
using namespace std;
int main()
{
	int L,R,C;
	cin>>L>>R>>C;
	int ans=1e9;
	for(int i=L;i<=R&&i-L<=10000;i++)
	{
		ans=min((long)ans,(1000-(long)i*C%1000)%1000);
	}
	cout<<ans<<endl;
}