蟠桃记

 1 #include <iostream>
 2 #include <algorithm>
 3 using namespace std;
 4 
 5 int main(){
 6     long long n;
 7     while (cin >> n){
 8         if (n == 0){
 9             //cout << 1 << endl;
10             continue;
11         }
12         int ans = 1;
13         for (int i = n - 1; i >= 1; i--){
14             ans = (ans + 1) * 2;
15         }
16         cout << ans << endl;
17     }
18 
19     //system("pause");
20     return 0;
21 }