record

code

#include<bits/stdc++.h>
using namespace std;
vector<int>tree;
void build(){
	const int s=tree.size();
	int l=0;
	while(l!=tree.size()){
		if(l==tree.size())break;
		for(register int i=l+1;i<l+l;i+=2)
			tree.push_back(max(tree[i-1],tree[i]));
		l+=l/2;
	}
}
int main(){
	int n;
	scanf("%d",&n);
	for(register int i=0;i<pow(2,n);++i){
		int x;
		cin>>x;
		tree.push_back(x);
	}
	build();
	cout<<min(tree[tree.size()-2],tree[tree.size()-3])<<endl;
	return 0;
}