func_code_string: #include <bits/stdc++.h>   using namespace std;   int Day12[] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};   int prime100[] = {2,  3,  5,  7,  11, 13, 17, 19, 23, 29, 31, 37,  41, 43,                     47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103};   template <typename T>   inline bool isLeap(T y) {     return (y % 400 == 0) || (y % 100 ? y % 4 == 0 : false);   }   template <typename T>   inline T GCD(T a, T b) {     a = abs(a);     b = abs(b);     if (a < b) swap(a, b);     while (b) {       a = a % b;       swap(a, b);     }     return a;   }   template <typename T>   inline T LCM(T x, T y) {     T tp = GCD(x, y);     if ((x / tp) * 1. * y > 9e18) return 9e18;     return (x / tp) * y;   }   template <typename T>   inline T BIGMOD(T A, T B, T M = 1000000007) {     T ret = 1;     while (B) {       if (B & 1) ret = (ret * A) % M;       A = (A * A) % M;       B = B >> 1;     }     return ret;   }   template <typename T>   inline T BigMod(T A, T B, T M) {     T ret = 1;     while (B) {       if (B & 1) ret = (ret * A) % M;       A = (A * A) % M;       B = B >> 1;     }     return ret;   }   long long int MySqrt(long long int n) {     long long int p = sqrt(n);     if ((p + 1) * (p + 1) <= n)       return p + 1;     else if (p * p <= n)       return p;     else       return p - 1;   }   long long int MyPow(long long int x, long long int n) {     if (n == 0)       return 1;     else if (n % 2 == 0)       return MyPow(x * x, n / 2);     else       return x * MyPow(x * x, ((n - 1) / 2));   }   long long int modInverse(long long int n) {     return BIGMOD(n, (long long int)1000000007 - 2) % 1000000007;   }   void solve() {     long long int ans = 1, n;     cin >> n;     if (n % 2 == 1)       printf( 0 n );     else {       n /= 2;       for (int i = 1; i <= n; i++) ans *= 2;       printf( %lld n , ans);     }   }   char arr[505][505];   int Left[505][505];   int Right[505][505];   int Up[505][505];   int Low[505][505];   void Now() {     int n, m, cnt = 0;     cin >> n >> m;     for (int i = 0; i < n; i++) {       for (int j = 0; j < m; j++) {         cin >> arr[i][j];         if (arr[i][j] ==  * ) cnt++;       }     }     for (int i = 1; i < n; i++) {       for (int j = 0; j < m; j++) {         if (arr[i - 1][j] ==  * ) Up[i][j] += 1 + Up[i - 1][j];       }     }     for (int i = 0; i < n; i++) {       for (int j = 1; j < m; j++) {         if (arr[i][j - 1] ==  * ) Left[i][j] += 1 + Left[i][j - 1];       }     }     for (int i = n - 1; i >= 0; i--) {       for (int j = m - 2; j >= 0; j--) {         if (arr[i][j + 1] ==  * ) Right[i][j] += 1 + Right[i][j + 1];       }     }     for (int i = n - 2; i >= 0; i--) {       for (int j = m - 1; j >= 0; j--) {         if (arr[i + 1][j] ==  * ) Low[i][j] += 1 + Low[i + 1][j];       }     }     for (int i = 1; i < n - 1; i++) {       for (int j = 1; j < m - 1; j++) {         if (Left[i][j] > 0 && Up[i][j] > 0 && Right[i][j] > 0 && Low[i][j] > 0 &&             arr[i][j] ==  * ) {           if (Left[i][j] + Up[i][j] + Right[i][j] + Low[i][j] + 1 == cnt) {             printf( YES n );             exit(0);           }         }       }     }     printf( NO n );   }   int main() { solve(); }   