#include <bits/stdc++.h>
using namespace std;
#define MOD ((long long)(1e9 + 7))

int main(void) {
  int N;
  cin >> N;
  long long dp[N][3] = {};
  dp[0][1] = 1;
  for (int i = 1; i < N; i++) {
    dp[i][0] = (dp[i - 1][2] + dp[i - 1][1]) % MOD;
    dp[i][1] = (dp[i - 1][0]) % MOD;
    dp[i][2] = (dp[i - 1][1]) % MOD;
  }
  long long ans = (dp[N - 1][0] + dp[N - 1][1] + dp[N - 1][2]) % MOD;
  cout << ans << endl;

  return 0;
}