#include <bits/stdc++.h>
using namespace std;
void solve() {}
void no() {
  cout << "NO" << '\n';
  exit(0);
}
const long long maxn = 100050;
long long a[maxn];
long long psa[maxn];
signed main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  long long n;
  cin >> n;
  for (long long i = 1; i <= n; i++) {
    cin >> a[i];
  }
  long long len = n;
  for (long long i = 1; i <= n; i++) {
    if (a[i] != a[1]) {
      len = i - 1;
      break;
    }
  }
  for (long long i = 1; i <= n; i++) {
    psa[i] = psa[i - 1] + a[i];
  }
  if (n % len) no();
  for (long long i = len; i <= n; i += len) {
    long long sum = psa[i] - psa[i - len];
    if (sum and sum != len) {
      no();
    }
    if (i >= len * 2) {
      if (sum == psa[i - len] - psa[i - 2 * len]) {
        no();
      }
    }
  }
  cout << "YES" << '\n';
}
