#include<bits/stdc++.h>
using namespace std;
#define rep(i,a,b) for(int i=a;i<b;i++)


int mod = 1000;
int add(int x, int y) { return (x += y) >= mod ? x - mod : x; }
template<class... T> int add(int x, T... y) { return add(x, add(y...)); }
int mul(int x, int y) { return 1LL * x * y % mod; }
template<class... T> int mul(int x, T... y) { return mul(x, mul(y...)); }
int sub(int x, int y) { return add(x, mod - y); }
typedef long long ll;
typedef vector<int> Vec;
typedef vector<Vec> Mat;
Vec mulMatVec(Mat a, Vec b)
{
    int n = b.size(); Vec ret(n, 0);
    rep(i, 0, n) rep(j, 0, n) ret[i] = add(ret[i], mul(a[i][j], b[j]));
    return ret;
}
Mat mulMatMat(Mat a, Mat b)
{
    int n = a.size(); Mat ret(n, Vec(n, 0));
    rep(i, 0, n) rep(j, 0, n) rep(k, 0, n) ret[i][j] = add(ret[i][j], mul(a[i][k], b[k][j]));
    return ret;
}
Mat fastpow(Mat x, ll n)
{
    Mat ret(x.size(), Vec(x.size(), 0));
    rep(i, 0, x.size()) ret[i][i] = 1;
    while (0 < n) { if ((n % 2) == 0) { x = mulMatMat(x, x); n >>= 1; } else { ret = mulMatMat(ret, x); --n; } }
    return ret;
}
void printVec(Vec a) { cout << "[ "; rep(i, 0, a.size()) cout << a[i] << " "; cout << "]" << endl; }
void printMat(Mat a) { rep(i, 0, a.size()) printVec(a[i]); }
//-----------------------------------------------------------------------------------
int main() {
    int N; cin >> N;

    if (N == 0) {
        printf("1\n");
        return 0;
    }

    Mat ma(2, Vec(2, 0));
    ma[0][0] = ma[0][1] = 2;
    ma[1][0] = 1;

    Vec ve(2, 0);
    ve[0] = ve[1] = 2;

    ma = fastpow(ma, N - 1);
    ve = mulMatVec(ma, ve);

    int ans = ve[0];
    if (N % 2 == 0) ans = (ans - 1 + 1000) % 1000;
    cout << ans << endl;
}