#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <string.h>
#include <math.h>
#include <limits.h>

int Parent(i) {
    return i / 2;
}
int Left(i) {
    return 2 * i + 1;
}

int Right(i) {
    return 2 * i + 2;
}


void pref_in(int number_parent, int* arr_medium, int maX, int* medium) {
    int child = Left(number_parent);
    if (child < maX)
        if (arr_medium[child] != INT_MIN) {
            int razn = arr_medium[child] + arr_medium[number_parent];
            if (abs(razn) < (*medium))
                *medium = abs(razn);
            pref_in(child, arr_medium, maX, medium);
        }
    child = Right(number_parent);
    if (child < maX)
        if (arr_medium[child] != INT_MIN) {
            int razn = arr_medium[child] + arr_medium[number_parent];
            if (abs(razn) < (*medium))
                *medium = abs(razn);
            pref_in(child, arr_medium, maX, medium);
        }
}
void pref(int number_parent, int* arr, int maX, int* arr_medium) {
    int child = Left(number_parent);
    if (child < maX)
        if (arr[child] != INT_MIN) {
            arr_medium[child] = arr[child] - arr[number_parent];
            pref(child, arr, maX, arr_medium);
        }
        else {
            arr_medium[child] = INT_MIN;
        }
    child = Right(number_parent);
    if (child < maX)
        if (arr[child] != INT_MIN) {
            arr_medium[child] = arr[child] - arr[number_parent];
            pref(child, arr, maX, arr_medium);
        }
        else {
            arr_medium[child] = INT_MIN;
        }
}
int main() {
    FILE* F = fopen("input.txt", "r");
    int h;
    fscanf(F, "%d ", &h);
    int maX = pow(2, h + 1) - 1;
    int* tree = (int*)malloc(sizeof(int) * maX);
    char temp[13];
    int i = 0;
    int flag = 0;

    while (fscanf(F, "%s", temp) != EOF) {
        int lenght = strlen(temp);
        if (temp[0] == '-') {
            flag = 1;
            if (lenght == 1) {
                tree[i] = INT_MIN;
                flag = 0; i++;
                continue;
            }
        }
        int value = 0;
        for (int j = 0; j < lenght; j++) {
            if (temp[j] == '-')
                continue;
            value = value * 10 + (temp[j] - '0');
        }
        if (flag)
            value *= -1;
        tree[i] = value;
        i++;
        flag = 0;
    }
    int medium = INT_MAX;
    int* sum = (int*)calloc(maX, sizeof(int));
    pref(0, tree, maX, sum);
    pref_in(0, sum, maX, &medium);
    free(tree);
    free(sum);
    FILE* out = fopen("output.txt", "w");
    fprintf(out, "%d", medium);
    fclose(out);
}