#include <bits/stdc++.h>
using namespace std;

int main() {
    long long L, R, C;
    cin >> L >> R >> C;

	int ans = 1000;
	for( int i = L; i <= R; i++ ) {
		int a = i * C % 1000;
		if( a ) a = 1000 - a;
		ans = min( ans, a );
		if( ans == 0 ) break;
	}

	cout << ans << endl;
}