#include <iostream>
using namespace std;

int main(){
   int n;
   cin >> n;
   unsigned long long dp[n + 1];
   dp[1] = 1;
   dp[2] = dp[3] = 2;
   for(int i = 4;i <= n;i++) dp[i] = dp[i - 3] + dp[i - 2];
   cout << dp[n] % 10000000007 << endl;
}