肿么WA了

#include <bits/stdc++.h>
#include <iostream>
#include <stdio.h>

using namespace std;

int main ()
{
	ios::sync_with_stdio ( 0 );
	cin.tie ( 0 ), cout.tie ( 0 );
	long long n, a, b, c;
	cin >> n >> a >> b >> c;
	for ( long long i = 1; i <= a; i ++ )
	{
		n /= 2;
	}
	for ( long long i = 1; i <= b; i ++ )
	{
		n += 1;
		n /= 2;
	}
	for ( long long i = 1; i <= c; i ++ )
	{
		if ( n == 0 )
		{
			break;
		}
		else
		{
			n -= 1;
			n /= 2;
		}
	}
	cout << n << endl;
	return 0;
}