program RemoveMiddleChars;
function RemoveMiddleChars(const str: string; N: Integer): string;
var
len, start: Integer;
begin
len := Length(str);
start := (len - N) div 2;
RemoveMiddleChars := Copy(str, 1, start) + Copy(str, start + N + 1, len);
end;
var
str, resultStr: string;
N: Integer;
begin
str := 'abc123def';
N := 3;
resultStr := RemoveMiddleChars(str, N);
WriteLn(resultStr);
end.
(*
run:
abcdef
*)