{$q-,r-,s-}
program pku1088;
const
  d1:array[1..4]of integer=(-1,0,1,0);
  d2:array[1..4]of integer=(0,1,0,-1);
var
  m,n,i,j,k,min,max,x,y,p,q:integer;
  c,len:array[1..100,1..100]of integer;
  b:array[1..100,1..100]of boolean;

function check:boolean;
  var
    i,j:integer;
  begin
    check:=false;
    for i:=1 to m do
      for j:=1 to n do
        begin
          if b[i,j]
            then  begin
                    check:=true;
                    exit;
                  end;
        end;
  end;

procedure mmin;
  var
    i,j:integer;
  begin
    min:=maxint;
    for i:=1 to m do
      for j:=1 to n do
        begin
          if b[i,j] and(c[i,j]<min)
            then begin
                   min:=c[i,j];
                   x:=i;y:=j;
                 end;
        end;
  end;

begin
  fillchar(c,sizeof(c),0);
  fillchar(len,sizeof(len),0);
  fillchar(b,sizeof(b),true);
  readln(m,n);
  for i:=1 to m do
    begin
      for j:=1 to n do
        begin
          read(c[i,j]);
        end;
      readln;
    end;
  mmin;len[x,y]:=1;
  while check do
    begin
      mmin;b[x,y]:=false;
      for i:=1 to 4 do
      begin
        if (x+d1[i]<=m)and(x+d1[i]>0)and(y+d2[i]<=n)
          and(y+d2[i]>0)
          then begin
                 if (c[x+d1[i],y+d2[i]]>c[x,y])
                 and(len[x+d1[i],y+d2[i]]<len[x,y]+1)
                   then len[x+d1[i],y+d2[i]]:=len[x,y]+1;
               end;
      end;
    end;
  max:=0;
  for i:=1 to m do
    for j:=1 to n do
     if len[i,j]>max
        then max:=len[i,j];
  writeln(max);
end.