program mn;
uses crt;
var a:array[1..100,1..100]of integer;
i,j,n,k,z:integer;
BEGIN
ClrScr;
Write('N:');readln(n);
for i:=1 to n do
begin
for j:=1 to n do
begin
a[i,j]:=random(40);
write(a[i,j]:4);
end;
writeln;
end;
writeln;
k:= n div 2;
for j:=1 to n do
begin
z:=a[k,j];
a[k,j]:=a[k+1,j];
a[k+1,j]:=z;
end;
for i:=1 to n do
begin
for j:=1 to n do
Write(a[i,j]:4);
writeln;
end;
readln;
END.