function solve(arr) {

let sequence = arr.shift().split(' ');

let i = 0;


  while (arr[i] !== 'end') {

    let arr2 = arr[i].split(' ').map(Number);

    let index1 = Number(arr2[0]);

    let index2 = Number(arr2[1]);


    if (index1 === index2 || index1 < 0 || index1 > sequence.length - 1 || index2 < 0 || index2 > sequence.length - 1) {

      let cenOfSeq = sequence.length / 2;

      sequence.splice(cenOfSeq, 0, `-${i + 1}a`);

      sequence.splice(cenOfSeq, 0, `-${i + 1}a`);

      console.log(`Invalid input! Adding additional elements to the board`);


    } else if (sequence[index1] === sequence[index2]) {

      console.log(`Congrats! You have found matching elements - ${sequence[index1]}!`);

      let indexHolder = sequence[index1];

     sequence = sequence.filter(el => el !== indexHolder);

      if (sequence.length === 1) {

        sequence = [];

      }


    } else {

      console.log(`Try again!`);

    }

    if (sequence.length === 0) {

      console.log(`You have won in ${i + 1} turns!`);

      return;

    }

    i++;
  }


  console.log(`Sorry you lose :(
${sequence.join(' ')}`);


  }