#include <iostream>
#include <vector>
#include <algorithm>
#include <array>
#define repeat(i,n) for (int i = 0; (i) < (n); ++(i))
typedef long long ll;
using namespace std;
constexpr ll mod = 1000000007;
int main() {
    int n; cin >> n;
    vector<array<ll,3> > dp(n+1);
    dp[0][0] = 1;
    repeat (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];
    }
    cout << (accumulate(dp[n].begin(), dp[n].end(), 0ll) % mod) << endl;
    return 0;
}