z.cpp

// https://www.acmicpc.net/problem/1074
#include <bits/stdc++.h>

using namespace std;

int rec(int, int, int);

int main(void)
{
    ios::sync_with_stdio(false);
    cin.tie(NULL);

    int n, r, c;
    cin>>n>>r>>c;
    cout << rec(n,r,c);

    return 0;
}

int rec(int n, int r, int c)
{
    if (n==0) {

        return 0;
    }

    int half = 1<<(n-1);
    if (r<half && c<half) {

        return rec(n-1,r,c);
    } 
    else if (r<half && c>=half) {

        return half*half+rec(n-1,r,c-half);
    } 
    else if (r>=half && c<half) {

        return 2*half*half+rec(n-1,r-half,c);
    } 
    else if (r>=half && c>=half) {

        return 3*half*half+rec(n-1,r-half,c-half);
    }

    return -1;
}