#include<bits/stdc++.h>
using namespace std;
int main(){
    int m,i;
    cin>>m;
    int a[i];
    for(i=0;i<m;i++){
    	cin>>a[i];
    }
	for(i=1;i<m-1;i++){
		if(a[i-1]&&a[i+1]){
			cout<<a[i]<<endl;
		}
	}
	
}

/**************************************************************
	Problem: 1153
	User: fuyijun
	Language: C++
	Result: Wrong Answer
****************************************************************/