#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (int)(n); i++)
#define rrep(ri,n) for(int ri = (int)(n-1); ri >= 0; ri--)
#define rep2(i,x,n) for(int i = (int)(x); i < (int)(n); i++)
#define rrep2(ri,x,n) for(int ri = (int)(n-1); ri >= (int)(x); ri--)
#define repit(itr,x) for(auto itr = x.begin(); itr != x.end(); itr++)
#define rrepit(ritr,x) for(auto ritr = x.rbegin(); ritr != x.rend(); ritr++)
#define ALL(x) x.begin(), x.end()
using ll = long long;
using namespace std;

bool fc(set<ll> &se, ll now){
  if(now < 1) return false;
  if(now == 1) return true;
  se.insert(now);
  bool res = false;
  rep(i, 3){
    if(se.find(now+1+i*2) != se.end()){
      if(se.find(now-3+i) == se.end()){
        res = fc(se, now-3+i);
        if(res == true) return res;
      }
    }
  }
  rep(i, 3){
    if(se.find(now-1-i*2) != se.end()){
      if(se.find(now-4-i) == se.end()){
        res = fc(se, now-4-i);
        if(res == true) return res;
      }
    }
  }
  return false;
}

int main(){
  set<ll> se;
  ll n;
  int k;
  cin >> n >> k;
  vector<ll> in(k);
  rep(i, k) cin >> in.at(i);
  for(auto now : in){
    bool f = fc(se, now);
    if(f == true){
      cout << "No" << endl;
      return 0;
    }
  }
  cout << "Yes" << endl;
  return 0;
}