How do I count all possible sums of array elements

I’m kind of stuck with my code and I can’t find where the problem is. My task is to find the closest sum in the array to the x value and amount of indexes to sum must not exceed n-value. Indexes to sum might not be consecutive, so the closest sum might be indexes(0,2,3) instead of (0,1,2). I’ve written some code, but it does not work with n value bigger than 4.

In my code value of sums(n) if called «towns» and x value is called «miles».

Here comes the code

  for(int i=0;i<ls.size();i++){
       sum=ls.get(i);
      counterTowns=1;
          if(sum<miles&&counterTowns<towns){
        for(int j=i+1;j<ls.size();j++){
                sum+=ls.get(j);
                counterTowns++;
                if(counterTowns==towns){
                    if(sum<=miles){
                        if(sum>temp){
                            result=sum;
                        }
                        temp=result;
                  }

                    sum=ls.get(i);
                    counterTowns=1;
             if(towns>2){   // I think the problem is in this line
                    j--;
                }
            }
        }
    }
}

So it works just fine for towns<=3, but with bigger amounts it skips some values. I hope my question is clear and if not fell free to ask any questions. Thank you in advance. Peace and love!!!