#include <iostream>
#include <vector>

#define MOD 1000000007
using namespace std;

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