#include <bits/stdc++.h>
using namespace std;
//ifstream in("txt.in");
//ofstream out("txt.out");
bool a[100005];
int n;
int main()
{
    ios::sync_with_stdio(0);
    cin >> n;
    for(int i=1; i<=n; i++)
        cin >> a[i];

    int lg=1;
    for(int i=2; i<=n; i++)
        if( a[i] != a[i-1] ) break;
        else lg++;
    if( lg == n ) return cout << "YES", 0;

     a[++n] = !a[n-1];
    int cnt=1;
    for(int i=2; i<=n; i++)
    {
        if( a[i-1] == a[i]) cnt++;
        else if( cnt != lg )  return cout << "NO",0; else cnt = 1;
    }
      cout << "YES";
    return 0;
}