#include <iostream>
using namespace std;

int main()
{
    int L,R,C,A;
    A = 1000;
    cin >> L >> R >> C;
    for (int i = L; i < R+1; i++){
        if (A > ((i * C - 1) / 1000 + 1) * 1000 - i * C) {
            A = ((i * C - 1) / 1000 + 1) * 1000 - i*C;
        }
        //cout << (i*C-1) << " " << ((i * C-1) / 1000 + 1) << " " << A << endl;
    }
    cout << A << endl;
    return 0;
}