var v:array[..] of boolean;

     a:array[..] of longint;

     b:array[..] of longint;

     ans:array[..,..] of longint;

     i,j,n,m,t:longint;

 procedure swap(var a,b:longint);

   var c:longint;

   begin

     c:=a;

     a:=b;

     b:=c;

   end;

 procedure sort(l,r:longint);

   var i,j,x:longint;

   begin

     i:=l;

     j:=r;

     x:=a[(l+r) shr ];

     repeat

       while a[i]<x do inc(i);

       while x<a[j] do dec(j);

       if not(i>j) then

       begin

         swap(a[i],a[j]);

         inc(i);

         dec(j);

       end;

     until i>j;

     if l<j then sort(l,j);

     if i<r then sort(i,r);

   end;

 function find(l,r,x:longint):longint;

   var m:longint;

   begin

     while l<=r do

     begin

       m:=(l+r) shr ;

       if a[m]=x then exit(m);

       if a[m]>x then r:=m- else l:=m+;

     end;

     exit(-);

   end;

 procedure check(i:longint);

   var j,k,p,x,y:longint;

   begin

     fillchar(v,sizeof(v),false);

     fillchar(b,sizeof(b),);

     if (a[]+a[]-a[i]) mod <> then exit;

     b[]:=(a[]+a[]-a[i]) div ;

     b[]:=a[]-b[];

     b[]:=a[]-b[];

     v[]:=true; v[]:=true; v[i]:=true;

     p:=;

     for j:= to n do

     begin

       while (p<=m) and v[p] do inc(p);

       if p>m then exit;

       b[j]:=a[p]-b[];

       v[p]:=true;

       for k:= to j- do

       begin

         if b[k]>=b[j] then exit;

         x:=find(,m,b[k]+b[j]);

         if x=- then exit;

         y:=x;

         while (y>) and (a[y]=a[x]) do dec(y);

         inc(y);

         while (y<=m) and (a[y]=a[x]) and v[y] do inc(y);

         if (y>m) or (a[y]<>a[x]) or v[y] then exit;

         v[y]:=true;

       end;

     end;

     inc(t);

     ans[t]:=b;

   end;

 begin

   readln(n);

   m:=(n-)*n div ;

   for i:= to m do

     read(a[i]);

   sort(,m);

   for i:= to n+ do

     if a[i]<>a[i-] then check(i);

   writeln(t);

   for i:= to t do

   begin

     for j:= to n do

       write(ans[i,j],' ');

     writeln;

   end;

 end.