#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef pair<ll,ll> P;
typedef vector<ll> VI;
typedef vector<VI> VVI;
#define REP(i,n) for(int i=0;i<(n);i++)
#define ALL(v) v.begin(),v.end()
template<typename T> bool chmax(T& x, const T& y){return (x<y)?(x=y,true):false;};
template<typename T> bool chmin(T& x, const T& y){return (x>y)?(x=y,true):false;};
constexpr ll MOD=998244353;
constexpr ll INF=2e18;
 
int main(){
    ll l, r, c; cin >> l >> r >> c;
    ll ans=INF;
    VI f(1000,0);
    for(ll i=l;i<=r;i++){
        ll x=1000-i*c%1000;
        if(x==1000)
            x=0;
        if(f[x])
            break;
        f[x]=1;
        chmin(ans,x);
    }
    cout << ans << endl;
    return 0;
}