{扩散 NOIP模拟2010-11-18
 Author: yangbohua
 Time: 2010-11-18}

program ppg;
var
  x,y:array[0..5000] of longint;
  n,i,j:longint;
  max,temp:longint;

begin
  assign(input,'ppg.in');
  reset(input);
  assign(output,'ppg.out');
  rewrite(output);
  readln(n);
  for i:=1 to n do
    readln(x[i],y[i]);
  max:=0;
  for i:=1 to n-1 do
    for j:=i+1 to n do
    begin
      temp:=abs(x[i]-x[j])+abs(y[i]-y[j]);
      if temp mod 2 = 0
        then temp:=temp div 2
        else temp:=(temp div 2)+1;
      if temp>max then max:=temp;
    end;
  writeln(max);
  close(input);
  close(output);
end.