function solve (arr) {

      arr = arr.sort((a, b) => a.localeCompare(b));

      let obj = {};


      // console.log(arr);


      for (let i = 0; i < arr.length; i++) {

        let j = i;

        while (arr[j][0].localeCompare(arr[i][0]) === 0) {

          let key = arr[i].split(' : ').filter(el => isNaN(el) ? el : false).join('');

         key = key + ":";

          let value = arr[i].split(' ').filter(el => Number(el) ? el : false).join('');

          obj[key] = value;

          i++;

          if (i > arr.length - 1) {

            break;

          }

        }

        console.log(arr[j][0]);

        for (let key in obj) {

          console.log(`  ${key} ${obj[key]}`);

        }

        obj = {};

        i--;


      }



    }