#include <bits/stdc++.h>
using namespace std;
long long n, K, l, r, mid;
long long calc(long long len, long long x) {
  if (len <= 2 * x) return 0;
  long long cnt[2] = {1, 0}, a[2] = {len, len - 1};
  long long res = 0, tmp;
  while (a[0] >= 2 * x + 1) {
    res += cnt[0];
    res += (a[1] >= 2 * x + 1) * cnt[1];
    tmp = a[0] / 2;
    if (a[0] & 1)
      cnt[0] = cnt[0] * 2 + cnt[1];
    else
      cnt[1] = cnt[1] * 2 + cnt[0];
    a[0] = tmp;
    a[1] = tmp - 1;
  }
  return res;
}
long long solve(long long l, long long r, long long limit, long long K) {
  long long mid = (l + r) >> 1, tmp, tmp2;
  if (K == 1) return mid;
  tmp = calc(mid - l, limit);
  tmp2 = calc(r - mid, limit + 1);
  if (K <= tmp + tmp2 + 1) return solve(l, mid - 1, limit, K - tmp2 - 1);
  return solve(mid + 1, r, limit, K - tmp - 1);
}
int main() {
  scanf("%I64d%I64d", &n, &K);
  if (K == 1) return puts("1"), 0;
  if (K == 2) return printf("%I64d\n", n), 0;
  n -= 2;
  K -= 2;
  l = 0;
  r = (n + 1) / 2;
  while (l < r) {
    mid = (l + r + 1) >> 1;
    if (calc(n, mid) >= K)
      l = mid;
    else
      r = mid - 1;
  }
  printf("%I64d\n", solve(1, n, l, K) + 1);
  return 0;
}
