#include <bits/stdc++.h>
using namespace std;
int main() {
  int N;
  cin >> N;
  vector<int> a(N);
  for (int i = 0; i < N; i++) cin >> a[i];
  if (N == 3) {
    if (a[0] != a[1] && a[1] != a[2] && a[2] != a[0]) {
      cout << "Yes" << endl;
    } else
      cout << "No" << endl;
    return 0;
  }
  if (N % 3 != 0) {
    for (int i = 0; i < N; i++) {
      if (a[i] != 0) {
        cout << "No" << endl;
        return 0;
      }
    }
    cout << "Yes" << endl;
    return 0;
  }
  int u[3];
  int idx = 1;
  u[0] = a[0];
  u[1] = a[0];
  int i = 1;
  while (idx < 3) {
    if (u[idx - 1] != a[i] && u[0] != a[i]) {
      u[idx] = a[i];
      idx++;
    }
    i++;
  }
  for (int i = 0; i < N; i++) {
    if (a[i] == u[0] || a[i] == u[1] || a[i] == u[2])
      continue;
    else {
      cout << "No" << endl;
      return 0;
    }
  }
  cout << "Yes" << endl;
}
