val len = LongArray(51, { 1L })
val nPans = LongArray(51, { 1L })

fun count(N: Int, X: Long): Long {
    val mid = (len[N]+1L)/2L
    return if(N==0 && X==1L) {
        1L
    } else if (X==1L) {
        0L
    }
    else if(X==len[N]) {
        nPans[N]
    } else if(X == mid) {
        nPans[N-1] + 1
    } else if (X < mid) {
        count(N - 1, X-1)
    } else if (X > mid){
        nPans[N-1] + count(N-1, X-mid) + 1
    } else {
        0L
    }
}


fun main(args: Array<String>) {
    val (N,X) = readLine()!!.split(" ").map { it.toLong() }
    val NN = N.toInt()

    // preprocessing
    for (i in 1 until 51) {
        len[i] = 2 * len[i-1] + 3
        nPans[i] = 2 * nPans[i-1] + 1
    }
//    assert(len[0] == 1L)
//    assert(len[1] == 5L)
//    assert(len[2] == 13L)
//    assert(nPans[0] == 1L)
//    assert(nPans[1] == 3L)
//    assert(nPans[2] == 7L)
//    assert(count(2, 1L) == 0L)
//    assert(count(2, 4L) == 2L)
//    assert(count(2, 7L) == 4L)
//    assert(count(2, 9L) == 5L)
//    assert(count(2, 10L) == 6L)
//    assert(count(2, 11L) == 7L)
//    assert(count(2, 13L) == 7L)
//    assert(count(50, 4321098765432109L) == 2160549382716056L)

    val ans = count(NN, X)
    println(ans)
}