#include <bits/stdc++.h>
using namespace std;
long long int power(long long int x, long long int y, long long int p) {
  long long int res = 1;
  x = x % p;
  if (x == 0) return 0;
  while (y > 0) {
    if (y & 1) res = (res * x) % p;
    y = y >> 1;
    x = (x * x) % p;
  }
  return res;
}
bool sortinrev(const pair<vector<int>, int>& a,
               const pair<vector<int>, int>& b) {
  if (a.first == b.first) return b.second > a.second;
  return a.first > b.first;
}
void DFS(vector<int> adj[], vector<bool>& visited, int u, int n,
         vector<int>& vi) {
  visited[u] = true;
  vi.push_back(u);
  for (int i = 0; i < adj[u].size(); i++) {
    if (visited[adj[u][i]] == false) {
      (DFS(adj, visited, adj[u][i], n, vi));
    }
  }
}
void run(vector<int> v) {
  for (int i = 0; i < v.size(); i++) cout << v[i] << " ";
  cout << endl;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  ;
  int n;
  cin >> n;
  int a[n];
  for (int i = 0; i < n; i++) {
    cin >> a[i];
  }
  stack<int> s;
  unordered_map<int, int> v;
  for (int i = 0; i < n; i++) {
    if (!s.empty()) {
      if (s.top() == a[i]) {
        s.push(a[i]);
      } else {
        v[s.size()]++;
        while (!s.empty()) {
          s.pop();
        }
        s.push(a[i]);
      }
    } else {
      s.push(a[i]);
    }
  }
  v[s.size()]++;
  if (v.size() == 1)
    cout << "YES";
  else
    cout << "No";
  return 0;
}
