// console.log('this is a debug message');

function solution(A) {
    A.sort(function (a, b){return a-b;});
    var res = 1;
    var counts = {};

    for (var i = 0; i < A.length; i++) {
      var num = A[i];
      counts[num] = counts[num] ? counts[num] + 1 : 1;
    }
    var ancienV,ancienO,res=1;
    for (var value in counts) {
      var occ = counts[value];
      console.log(value+' '+occ);
      //console.log(ancien[obj])
      res = Math.max(res,occ)
      if((Math.abs(ancienV-value)<=1)){
        res = Math.max(res,Math.abs(occ-ancienO))
      }
      ancienV = value
      ancienO = occ
    }
    //console.log(res)
    return res
}


console.log(
    solution(
        [2,5,4,7,8,9,15,2]
    )
)