#include <bits/stdc++.h>
using namespace std;
const int N = 100010, Mod = 998244353;
const double pi = acos(-1.0);
int a[N], n, w[N], b[N], temp1, temp2;
vector<int> temp;
int main() {
  cin >> n;
  for (int i = 1; i <= n; i++) cin >> a[i];
  for (int i = 1; i <= n; i++) {
    if (a[i] == 1) {
      b[i] = 1;
      if (a[i - 1] == a[i]) b[i] += b[i - 1];
    }
  }
  for (int i = 1; i <= n; i++)
    if (b[i] == 0 && b[i - 1] != 0) temp.push_back(b[i - 1]);
  if (b[n] != 0) temp.push_back(b[n]);
  for (int i = 1; i < temp.size(); i++)
    if (temp[i] != temp[i - 1]) {
      cout << "NO\n";
      return 0;
    }
  a[0] = 1;
  if (temp.size())
    temp1 = temp[0];
  else {
    cout << "YES\n";
    return 0;
  }
  temp.clear();
  for (int i = 1; i <= n; i++) {
    if (a[i] == 0) {
      w[i] = 1;
      if (a[i - 1] == a[i]) w[i] += w[i - 1];
    }
  }
  for (int i = 1; i <= n; i++)
    if (w[i] == 0 && w[i - 1] != 0) temp.push_back(w[i - 1]);
  if (w[n] != 0) temp.push_back(w[n]);
  for (int i = 1; i < temp.size(); i++)
    if (temp[i] != temp[i - 1]) {
      cout << "NO\n";
      return 0;
    }
  temp2 = temp[0];
  if (temp1 != temp2)
    cout << "NO\n";
  else
    cout << "YES\n";
  return 0;
}
