#include <bits/stdc++.h>
using namespace std;
struct th {
  long long num, len, ans;
  th(long long a, long long b) { num = a, len = b; }
  bool operator<(const th &a) const {
    if (num != a.num) return num < a.num;
    return len < a.len;
  }
};
set<th> ans;
long long get(long long len, long long num) {
  th new1 = th(num, len);
  set<th>::iterator it = ans.find(new1);
  if (it != ans.end()) return (*it).ans;
  long long mid = (1 + len) >> 1;
  new1.ans = 0;
  if (mid - 1 >= num) new1.ans = 1 + get(mid, num) + get(len - mid + 1, num);
  ans.insert(new1);
  return new1.ans;
}
long long gpl(long long len, long long num, long long id) {
  if (len == 1) return 1;
  long long mid = (1 + len) >> 1;
  long long ans = 0;
  if (id == 1)
    ans = mid;
  else {
    long long lans = get(mid, num);
    long long rans = get(len - mid + 1, num + 1);
    if (lans + rans + 1 >= id && lans)
      ans = gpl(mid, num, id - rans - 1);
    else
      ans = mid - 1 + gpl(len - mid + 1, num, id - lans - 1);
  }
  return ans;
}
int main() {
  long long n, k;
  scanf("%I64d%I64d", &n, &k);
  if (k == 1) {
    puts("1\n");
    return 0;
  }
  if (k == 2) {
    printf("%I64d\n", n);
    return 0;
  }
  k -= 2;
  long long l = 0, r = n;
  while (l < r) {
    long long mid = (l + r) >> 1;
    if (get(n, mid + 1) >= k)
      l = mid + 1;
    else
      r = mid;
  }
  printf("%I64d\n", gpl(n, l, k));
  return 0;
}
