Here is my PHP solution

s); arr[0];

    if(count(`$arr) == 1 || $`initial == 0)
    {
          $ans = 'NO';   
    }
    else
    {

    $ans = 'NO';
    `$len = count($`arr);
    `$iteration = floor($`len/2)+1;

     $firstNum = 0;
    for (`$i=$`iteration; `$i > 0; $`i--) { 

        `$str = substr($`s, 0,$i);
        `$strlen = strlen($`str);
        `$second = substr($`s, `$i, $`strlen);
        `$third = substr($`s, `$i, $`strlen+1);

          if(((int)`$second - (int)$`str == 1)||((int)`$third - (int)$`str == 1))
          {

            `$firstNum = $`str;
            break;
          }
    }

     `$ans = 'YES  '.$`firstNum;
    `$newString = substr($`s, strlen((string) $firstNum));



    `$result = (int)$`firstNum;
    while ($newString!=='') {
          `$result = $`result+1;

            if (substr(`$newString, 0, strlen($`result)) == $result) {


             `$newString = substr($`newString, strlen((string) $result));

          }
          else
          {

             $ans = 'NO';
             break;
          }
    }

    }