is_mirror_recursive.cpp

#include<iostream>

using namespace std;

bool is_mirror(int n) {
    if (n<=0) return true;
    int n1, n2;
    cin >> n1;
    if (n==1) return true;
    bool inner_mirror = is_mirror(n-2);
    cin >> n2;
    return inner_mirror && n1 == n2;
}

int main(void) {
	int n;
	cin >> n;
	cout << (is_mirror(n) ? "YES" : "NO") << endl;
}