//#include<bits/stdc++.h>
#include<iostream>
#include<string>
#include<iomanip>
#include<cmath>
#include<algorithm>
using namespace std;
//Do whatever you can ^^
int max(int arr[], int n)
{
int max = arr[0];
for (int i = 1; i < n; i++)
{
if (max < arr[i])
max = arr[i];
}
return max;
}
int min(int arr[], int n)
{
int min = arr[0];
for (int i = 1; i < n; i++)
{
if (min> arr[i])
min = arr[i];
}
return min;
}
int main()
{
//cout << fixed << setprecision(9);
//freopen("Files.in", "r", stdin);
//freopen("Files.out", "w", stdout);
std::ios_base::sync_with_stdio(NULL);
cin.tie(NULL); cout.tie(NULL);
int n;
cin >> n;
long long arr[1000000];
for (int i = 0; i < n; i++)
{
cin >> arr[i];
}
for (int i = 0; i < n - 1; i++)
{
if (arr[i] == arr[i + 1])
{
arr[i] = 0;
arr[i + 1] = 0;
}
}
for (int i = 0; i < n; i++)
{
if (arr[i] != 0)
{
cout << "NO\n";
return 0;
}
}
cout << "YES\n";
// system("pause");
}
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