rt,蒟蒻 70pts 求调。
#include <bits/stdc++.h>
using namespace std;
#define ll unsigned long long
const ll m = 1e9 + 7;
ll qpow(ll x, ll p) {
ll res = 1;
while (p > 0) {
if (p & 1) {
res = (res % m * x % m) % m;
}
p >>= 1;
x = (x % m * x % m) % m;
}
return res % m;
}
ll ans, n;
int main() {
cin >> n;
ans = (n % m * qpow(2, n - 1) % m) % m - (qpow(2, n) % m) + 1;
cout << ans << endl;
return 0;
}