#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); i++)
using namespace std;
using ll = long long;
using ld = long double;
using uint = unsigned int;
using ull  = unsigned long long;
template < class T > bool chmin(T& a, T b) { if(a > b) { a = b; return true; } return false; }
template < class T > bool chmax(T& a, T b) { if(a < b) { a = b; return true; } return false; }

int main(){
    cin.tie(0);
    ios::sync_with_stdio(0);
    
    ll L,R,C; cin >> L >> R >> C;
    ll ans = 1000;
    for(ll x = L; x <= min(L + 1000, R); x++) {
        ll m = (C * x) % 1000;
        if(m == 0) chmin(ans, 0LL);
        else chmin(ans, 1000 - m);
    }
    cout << ans << endl;
}