programmers.co.kr/learn/courses/30/lessons/12985
function solution(n,a,b)
{
(a%2 == 1) ? a ++ : null;
(b%2 == 1) ? b ++ : null;
if(a==b) return 1;
var cnt = 0;
while(!(a === b)){
a = Math.ceil(a/2);
b = Math.ceil(b/2);
cnt++;
}
return cnt;
}