#include <bits/stdc++.h>

using namespace std;

#define REP(i,n) for(int i=0; i<(int)(n); i++)

const long long MOD = 1e9 + 7;
long long dp[1000000+1][3];

int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);

  int n;
  cin >> n;

  dp[0][0] = 1;

  REP (i, 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];
  }

  long long sum = 0;
  REP (i, 3) sum += dp[n][i];
  sum %= MOD;

  cout << sum << endl;
  
  return 0;
}