#include "bits/stdc++.h"
using namespace std;
typedef long long ll;
#define int ll
typedef pair<int,int> pii;
#define rep(i,n) for(ll i=0;i<(ll)(n);i++)
#define all(a) (a).begin(),(a).end()
#define pb emplace_back
#define INF (1e9+1)

const ll MOD = 1e9+7;

signed main(){
    int n;
    cin>>n;
    if(n==1){
        cout<<1<<endl;
        return 0;
    }
    
    vector<int> dp(n+1,0);
    dp[0] = 1;
    rep(i,n){
        for(int step=2;step<=3;step++){
            if(i+step>n)continue;
            (dp[i+step] += dp[i])%=MOD;
        }
    }
    (dp[n] += dp[n-2] + dp[n-1])%=MOD;
    
    cout<<dp[n]<<endl;
}