/**********************************************************************************/
/*  Problem: c123 "Rails" from ACM 514                                            */
/*  Language: CPP (1077 Bytes)                                                    */
/*  Result: AC(24ms, 416KB) judge by this@ZeroJudge                               */
/*  Author: pcmslouis at 2013-04-29 16:00:49                                      */
/**********************************************************************************/


#include <iostream>
#include <cstdio>
#include <stack>

using namespace std;

//先簡單寫 
int main()
{
  int N, check[1000];

  while(scanf("%d", &N), N!=0)
  {
    int first;
    while(scanf("%d", &first), first!=0)
    {
      check[0] = first;
      for(int i=1; i<N; i++) //輸入 
        scanf("%d", &check[i]);          

      stack<int> mystack; //建立並清空stack
      int index = 0;      //跑check 
      int element = 1;    //首個放入的數字 

      while(index < N && element <= N+1)
      {
        if(mystack.empty()) //絕對PUSH 
        {
          mystack.push(element++);
        }
        else
            if(mystack.top()==check[index]) //比對符合則POP
            {
              mystack.pop();
              index++; //往下檢查 
            }
            else //無法POP則PUSH 
            {
              mystack.push(element++);
            }
      }

      if(mystack.empty()) //完全檢查 
        puts("Yes");
      else
        puts("No");

    }
    puts("");

  }

  return 0;    
}