#include<bits/stdc++.h>
using namespace std;
#define rep(i,n) for(ll i=0;i<n;i++)
#define repl(i,l,r) for(ll i=(l);i<(r);i++)
#define per(i,n) for(ll i=(n)-1;i>=0;i--)
#define perl(i,r,l) for(ll i=r-1;i>=l;i--)
#define fi first
#define se second
#define pb push_back
#define ins insert
#define pqueue(x) priority_queue<x,vector<x>,greater<x>>
#define all(x) (x).begin(),(x).end()
#define CST(x) cout<<fixed<<setprecision(x)
#define rev(x) reverse(x);
using ll=long long;
using vl=vector<ll>;
using vvl=vector<vector<ll>>;
using pl=pair<ll,ll>;
using vpl=vector<pl>;
using vvpl=vector<vpl>;
const ll MOD=1000000007;
const ll MOD9=998244353;
const int inf=2e9+1;
const ll INF=4e18;
const ll dy[8]={-1,0,1,0,1,1,-1,-1};
const ll dx[8]={0,-1,0,1,1,-1,1,-1};
template <typename T> inline bool chmax(T &a, T b) {
  return ((a < b) ? (a = b, true) : (false));
}
template <typename T> inline bool chmin(T &a, T b) {
  return ((a > b) ? (a = b, true) : (false));
}

ll mod=1000;//一次元ベクトルの高速化dp
vl matmul(vl &dp, vvl &mt){
    ll m=dp.size();
    vl ret(m,0); 
    rep(i,m)rep(j,m){
        ret[i]+=mt[i][j]*dp[j];
        ret[i]%=mod;
    }
    return ret;
}
vvl update(vvl &mt){
    ll m=mt.size();
    vvl ret(m,vl(m,0));
    rep(i,m)rep(j,m)rep(k,m){
        ret[i][j]+=mt[i][k]*mt[k][j];
        ret[i][j]%=mod;
    }
    return ret;
}
void matpow(vl &dp, vvl &mt, ll k){
    ll m=dp.size();
    while(k){
        if(k&1)dp=matmul(dp,mt);
        mt=update(mt);
        k/=2;
    }
}

int main(){
  ll n;cin >> n;
  vvl mat(2,vl(2,1));mat[0][1]=3;
  vl dp={1,0};
  matpow(dp,mat,n);
  //cout << dp[0] << endl;
  ll ans=dp[0];
  ans*=2;
  if(n%2==0)ans--;
  cout << (ans+mod)%mod << endl;
}