"use strict";

function _slicedToArray(arr, i) { return _arrayWithHoles(arr) || _iterableToArrayLimit(arr, i) || _nonIterableRest(); }

function _nonIterableRest() { throw new TypeError("Invalid attempt to destructure non-iterable instance"); }

function _iterableToArrayLimit(arr, i) { var _arr = []; var _n = true; var _d = false; var _e = undefined; try { for (var _i = arr[Symbol.iterator](), _s; !(_n = (_s = _i.next()).done); _n = true) { _arr.push(_s.value); if (i && _arr.length === i) break; } } catch (err) { _d = true; _e = err; } finally { try { if (!_n && _i["return"] != null) _i["return"](); } finally { if (_d) throw _e; } } return _arr; }

function _arrayWithHoles(arr) { if (Array.isArray(arr)) return arr; }

function main(input) {
  var lines = input.split('\n');

  var _splitNum = splitNum(lines.shift()),
      _splitNum2 = _slicedToArray(_splitNum, 2),
      N = _splitNum2[0],
      X = _splitNum2[1];

  var result = eat(N, X);
  console.log(result);
}

var memo = new Array(51).fill(-1);

function eat(n, remains) {
  if (n < 0) throw null;
  var full = height(n) <= remains;

  if (full && memo[n] >= 0) {
    return memo[n];
  }

  if (remains <= 0) {
    return 0;
  }

  if (n === 0) {
    return 1;
  }

  if (remains === 1) {
    return 0;
  }

  var res1 = eat(n - 1, remains - 1);
  var rem1 = remains - 1 - height(n - 1);

  if (rem1 <= 0) {
    return res1;
  }

  if (rem1 === 1) {
    return res1 + 1;
  }

  var res2 = eat(n - 1, rem1 - 1);

  if (full) {
    memo[n] = res1 + res2 + 1;
  }

  return res1 + res2 + 1;
}

function height(n) {
  return Math.pow(2, n + 2) - 3;
}

main(require('fs').readFileSync('/dev/stdin', 'utf8'));

function splitNum(line) {
  return line.split(/\s+/).map(function (n) {
    return parseInt(n);
  });
}
