В матрице размером n на m(1

const 
n=4;
m=5;
var
a:array[1..n,1..m] of integer;
i,j,pr:integer;
begin
for i:=1 to n do
    begin 
        for j:=1 to m do
          begin
            a[i,j]:=random(40);
            write('  ',a[i,j]:3);
          end;
        writeln();
    end;
writeln('--------') ; 

for j:=1 to m do
    begin
    pr:=a[1,j];
    a[1,j]:=a[n,j];
    a[n,j]:=pr;
    end;


writeln('--------') ; 

for i:=1 to n do
    begin 
        for j:=1 to m do
          begin
             write('  ',a[i,j]:3);
          end;
        writeln();
    end;
    
end.