#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll=long long;
using ld=long double;
ld pie=3.141592653589793;
ll inf=144494;
ll mod=1000000007;
int main(){
    ll l,r,c;
    cin >> l >> r >> c;
    ll ans=inf;
    vector<ll>memo(2000,0);
    for (ll i = l; i <=r; i++)
    {
        ll x=(1000-(i*c)%1000)%1000;
        if (memo[x]>=1)
        {
            break;
        }
        memo[x]+=1;
        ans=min(ans,x);
    }
    cout << ans << endl;
}