Else statement is overwriting my if statement in JS chronometer

I'm trying to create a chronometer, It works well when I don't add the typical zeroes before the 1 digit numbers, but when trying to create a logic that removes the zero it makes my code working not properly.

Please, run this working snippet:

        var n = 0;

        var m = 0;
        var h = 0;

        var n = ( n < 2 ) ? n = "0" + 2 : n.slice(-2) ;


        var scrubberCounter = document.getElementById("scrubberCounter");
        
          setInterval(function () {
              if(n.toString().length < 2 && m.toString().length < 2){
                scrubberCounter.innerHTML = h + ":" + "0" + m + ":" + "0" + n;

              }else{
                scrubberCounter.innerHTML = h + ":" + m + ":" +n;
              }

            n++;
            if (n ===20) {
        
              if (m < 20) {
                m++;
              } else {
                m = 0;
                h++;
              }
              n = 0;
            }
          }, 300);

    <table style='border: 1px solid orange; background: white;'><tr><td><font color='red' id='scrubberCounter'></font></td></tr></table>

Can you please lend me a hand? Thank you so much.