#include <atcoder/all>
using namespace std;
using mint = atcoder::modint1000000007;

int main(){
    int n;
    cin >> n;
    vector<array<mint, 3>> dp(n + 5);
    dp[1][0] = 1;
    dp[2][1] = 1;
    dp[3][2] = 1;
    for(int i = 1; i < n; i++){
        for(int j = 0; j < 3; j++){
            for(int k = 0; k < 3; k++){
                if(j == k)continue;
                dp[i + k + 1][k] += dp[i][j];
            }
        }
    }
    cout << (dp[n][0] + dp[n][1] + dp[n][2]).val() << '\n';
}