В заданной матрице X(N,M) (N<=10, M<=15). В каждом столбце поменять местами максимальный и минимальный элемент матрицы- Pascal(Паскаль)

Uses
  CRT;

Const
  nmmax = 20;

var
  A: array [1 .. nmmax, 1 .. nmmax] of integer;
  i, j, n, m, jmin, jmax, buf: integer;

Begin
  repeat
    Write('Vvedite kol-vo strok: ');
    Readln(n);
  until n in [1 .. nmmax];
  repeat
    Write('Vvedite kol-vo stolbcov: ');
    Readln(m);
  until m in [1 .. nmmax];
  randomize;
  for i := 1 to n do
  begin
    jmin := 1;
    jmax := 1;
    for j := 1 to m do
    begin
      A[i, j] := random(10) - 3;
      write(A[i, j]:3);
      if A[i, j] > A[i, jmax] then
        jmax := j
      else if A[i, j] < A[i, jmin] then
        jmin := j;
    end;
    writeln;
    buf := A[i, jmin];
    A[i, jmin] := A[i, jmax];
    A[i, jmax] := buf;
  end;
  writeln;
  for i := 1 to n do
  begin
    for j := 1 to m do
    begin
      write(A[i, j]:3);
    end;
    writeln;
  end;
  Readln

End.