#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
using ll=long long;
#define rep(i,n) for(int i=0;i<n;i++)
#define rrep(i,n) for(int i=(n)-1;i>=0;i--)
#define all(v) v.begin(),v.end()
#define rall(v) v.rbegin(),v.rend()
template<class T> bool chmax(T &a, T b){if (a < b){a = b;return true;} else return false;}
template<class T> bool chmin(T &a, T b){if (a > b){a = b;return true;} else return false;}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    ll l,r,c;
    cin>>l>>r>>c;
    ll ans=1LL<<60;
    for(ll x=l;x<l+1000;x++){
        if(x>r)break;
        if((c*x)%1000==0)ans=0;
        else chmin(ans,1000-c*x%1000);
    }
    cout<<ans<<"\n";
}