#include<iostream>
#include<algorithm>
using namespace std;
int main()
{
int count,flag,m;
long long int n,temp,t;
cin>>t;
while(t--)
{
flag=1;
count=1;
cin>>n>>m;
long long int unluck[m];
for(int i=0;i<m;i++)
cin>>unluck[i];
sort(unluck,unluck+m);
if(unluck[0]==1||unluck[m-1]==n) //unlucky tiles at beginning or end
flag=0;
int z=0;
while(z<m-1&&flag==1)
{
if(unluck[z+1]==unluck[z]+1)
count++;
else
count=1;
if(count>=3)//number of unlucky tiles
flag=0;
z++;
}
if(flag==0)
cout<<"NO"<<endl;
else
cout<<"YES"<<endl;
}
return 0;
}
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