#include <bits/stdc++.h>
#define ll long long int
using namespace std;
#define m 1000000007

int main(){
	ll k;
	cin>>k;
	ll s = k*k - (k-1);
	// cout << s << endl;
	s %= m;
	ll ans = 0;
	ans += s*k;
	ll n = k-1;
	ans += n*(n+1);
	ans %= m;
	cout << ans << endl;
}