where is my mistake? falls on 5th

var i,nr,n,k,c:integer;
begin
read(n,k);
nr:=trunc(n/2);
if (k>nr) then
begin
for i:=nr+1 to k-1 do
inc(c);
end;
if (k<nr) then
begin
for i:=k+1 to nr do
inc(c);
end;
write(c);
end.

Your code is very bad and solution is wrong too.
At first nr:=trunc(n/2) n is even because of this you could write nr=n div 2;
2.for i:=nr+1 to k-1 do
   inc(c); -----> this is very bad code.If you want something like that you should write
                c:=k-1-(nr+1)+1;
3.end here should be
    if (k > nr)
                Writeln(k -3)

            else
                WriteLn(n - k - 2);