#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define REP(i, n) for(int(i)=0;(i)<(n);++(i))
#define in(T,V) T V;cin>>V;
const int MOD = 1000;

// ((1+sqrt3)^n + (1-sqrt3)^n) - (1-sqrt3)^n
// |(1-sqrt3)^n| = (-0.73205...)^n < 1

struct OBJ{
    ll r,d;
    OBJ(ll r, ll d):r(r),d(d){};
    const OBJ operator*(const OBJ &p) const {
        ll resr = (r * p.r + d * p.d * 3) % MOD;
        ll resd = (d * p.r + p.d * r) % MOD;
        return OBJ(resr, resd);
    }
};

const OBJ binpow(OBJ x, ll k){
    if(k == 0) return OBJ(1,0);
    if(k % 2 == 0) return binpow(x*x, k/2);
    else return x * binpow(x, k-1);
}

int main(){
    in(int,N);
    OBJ res = binpow(OBJ(1,1), N);
    cout << (res.r * 2 - 1 + N % 2 + MOD) % MOD << endl;
}