#include <cstdio>

const int N = 1000000 + 10, MOD = 1000000007;

int n, f[N], g[N];

int main() {
  scanf("%d", &n);
  f[0] = g[0] = 1;
  f[1] = n, g[1] = n + 1;
  for (int i = 2; i <= n; ++i) {
    f[i] = (g[i - 1] - f[i - 2]) % MOD;
    f[i] = (f[i] + (n - 1LL) * (n - 1LL)) % MOD;
    f[i] = (f[i] + n - i + 1LL) % MOD;
    g[i] = (g[i - 1] + f[i]) % MOD;
  }
  printf("%d\n", (f[n] + MOD) % MOD);
  return 0;
}
