xoanoc

uses crt;
var n,i,j,s,canle:longint;
        a:array[1..1000,1..1000]of longint;
function check:boolean;
var i,j:longint;
begin
    check:=false;
    for i:=1 to n do
        for j:=1 to n do
            if a[i,j]=0 then begin check:=true; break end
end;
function sochuso:longint;
var d:longint;
begin
    d:=0;
    while s<>0 do begin inc(d); s:=s div 10 end;
    sochuso:=d;
end;
procedure phai;
begin inc(s); inc(j); a[i,j]:=s; end;
procedure trai;
begin inc(s); dec(j); a[i,j]:=s; end;
procedure tren;
begin inc(s); dec(i); a[i,j]:=s; end;
procedure duoi;
begin inc(s); inc(i); a[i,j]:=s; end;

begin
    write('N='); readln(n);
    for i:=1 to n do
        for j:=1 to n do
            a[i,j]:=0;
    i:=1; j:=1; a[1,1]:=1; s:=1;

    while check do
        begin
            while (j+1<=n) and (a[i,j+1]=0) do phai;
            while (i+1<=n) and (a[i+1,j]=0) do duoi;
            while (j-1>=1) and (a[i,j-1]=0) do trai;
            while (i-1>=1) and (a[i-1,j]=0) do tren;
        end;

    canle:=sochuso+1;
    for i:=1 to n do
        begin writeln;
                    for j:=1 to n do write(a[i,j]:canle);
        end;
    readln
end.