3. 删除奇数个字符

program ex_3;
var
     st : string;
     i, len : integer;
begin
     readln(st);
     len := length(st);
     for i := 1 to (len+1) div 2 do
         delete(st,i,1);
     writeln(st);
     readln;
end.


program ex_3;
var
     st : string;
     i, len : integer;
begin
     readln(st);
     len := length(st);
     for i := 1 to len div 2 do
          st[i] := st[i*2];
     st[0] := chr(i);
     writeln(st);
     readln;
end.