#include <bits/stdc++.h>   using namespace std;   int h;   int edge[5000];   int extend[5000];   int maximum;   int v[5000];   bool flag = 0;   void dfs_m(int p, int value) {     v[p] = value;     if (edge[p * 2] != 0)       dfs_m(p * 2 + 0, value + edge[p * 2]);     else {       if (maximum < value) maximum = value;     }     if (edge[p * 2 + 1] != 0)       dfs_m(p * 2 + 1, value + edge[p * 2 + 1]);     else {       if (maximum < value) maximum = value;     }   }   void dfs(int p, int value) {     if (edge[p * 2] != 0) {       dfs(p * 2, value + edge[p * 2] + extend[p * 2]);     } else {       if (value < maximum) {         extend[p] += (maximum - value);       }     }     if (edge[p * 2 + 1] != 0) {       dfs(p * 2 + 1, value + edge[p * 2 + 1] + extend[p * 2 + 1]);     } else {       if (value < maximum) {         extend[p] += (maximum - value);       }     }   }   int min(int a, int b) {     if (a == b) return -1;     if (a < b) {       return a;     }     return b;   }   void merge(int n) {     if (extend[n * 2] != 0 && extend[n * 2 + 1] != 0) {       int m = min(extend[n * 2 + 1], extend[n * 2]);       flag = false;       if (m == -1) {         extend[n] += extend[n * 2 + 1];         extend[n * 2] = extend[n * 2 + 1] = 0;         merge(n / 2);       } else {         extend[n] += m;         extend[n * 2] -= m;         extend[n * 2 + 1] -= m;         merge(n / 2);       }     }   }   int main() {     scanf( %d , &h);     int e = pow(2, h + 1) - 2;     memset(edge, 0, sizeof(edge));     memset(extend, 0, sizeof(extend));     memset(v, 0, sizeof(v));     for (int i = 2; i <= e + 1; i++) {       scanf( %d , &edge[i]);     }     maximum = 0;     dfs_m(1, 0);     dfs(1, 0);     int node = pow(2, h + 1);     for (int i = 2; i <= e + 1; i++) {       extend[i] /= 2;     }     while (true) {       flag = true;       for (int i = 0; i < node; i++) {         merge(i);       }       for (int i = 2; i <= e + 1; i++) {       }       if (flag) {         break;       }     }     int ans = 0;     for (int i = 0; i <= e + 1; i++) {       ans += extend[i];     }     printf( %d , ans);     return 0;   }   