program z106;</br>
  uses crt;</br>

  var i,j,n,m,cmx,mx:integer;</br>
  procedure max(var mx,n,m:integer;</br>
  const a:TMyArray);</br>
  Begin
  mx:=a[1,1];</br>
  for i:=1 to n do
  for j:=1 to m do
  if a[i,j]> mx then mx:=a[i,j];</br>
  end;</br>
  BEGIN
  max(mx,n,m,a);</br>
  i:=0;</br>
  repeat
  j:=0;</br>
  cmx:=0;</br>
  inc(i);</br>
  repeat
  inc(j);</br>
  if a[i,j]=mx then inc(cmx);</br>
  until (j=m) or (cmx=2);</br>
  until(i=n) or (cmx=2);</br>
  if cmx=2 then writeln('yes')
  else writeln('no');</br>
  END.




  END.