#include<iostream>
#include<algorithm>
#include<vector>
using namespace std;

static const int MOD=1000000007;

int main(){
    int N;
    cin >> N;
    vector<long long> dp(N+10);
    dp[0]=1;
    dp[1]=1;
    dp[2]=2;
    for(int i=0;i<=N;i++){
        dp[i+3]=(dp[i]+dp[i+1])%MOD;
    }
    cout << dp[N] << endl;
}