//  lanqiao 2110 (积木画)
#include<bits/stdc++.h>
using namespace std;
const int N = 10000010, MOD = 1e9 + 7;
int f[N];
/*
递推法:
f1=1 f2=2 f3=5 f4=11 f5=24 f6=53
f[n] = 2*f[n-1] + f[n-3]
*/
int main(){
    int n; cin >> n;
    f[1] = 1, f[2] = 2; f[3] = 5;
    for(int i = 4; i <= n; i++){
        f[i] = (2*f[n-1] % MOD + f[i-3] % MOD) % MOD;
    }
    cout << f[n] << endl;
    return 0;
}
/* test samples -> 5
3
*/