#include<bits/stdc++.h>
#define rep(i,a,b) for(int i=int(a);i<int(b);++i)
using namespace std;
typedef long long ll;
int INF = (1LL << 30) - 1;
int MOD = 1e9+7;
main(){
    int N;
    cin >> N;
    ll dp[N+1][3] = {};
    dp[2][0] = dp[1][1] = dp[2][2] = 1;
    rep(i,2,N){
        dp[i+1][0] = (dp[i][1] + dp[i][2]) % MOD;
        dp[i+1][1] = dp[i][0];
        dp[i+1][2] = dp[i][1];
    }
    ll ans = 0;
    rep(i,0,3)ans += dp[N][i];
    cout << ans % MOD<< endl;
}