#include <bits/stdc++.h>
using namespace std;
const int MAXN = 5e3 + 5;
int x,y;
bitset <MAXN> dp[MAXN],RNG,tmp;
//dp[i][j]means can (x,y) go to the point (x+i,y+j)
int main()
{
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	int n;
	cin >> n >> x >> y;
	dp[0][0] = 1;
	for (int i = 1,xl,xr,yl,yr; i <= n; i++)
	{
		cin >> xl >> xr >> yl >> yr;
		xl -= x,xl = max(xl,0),yl -= y,yl = max(yl,0);
		xr -= x,xr = min(xr,n),yr -= y,yr = min(yr,n);
		RNG.set(),RNG >>= (yr + 1),RNG <<= (yr + 1);
		RNG.flip(),RNG >>= yl,RNG <<= yl;//!!!位置(yl+1)~(yr+1)
		for (int j = xr; j >= xl; j--)
		{
			tmp = (dp[j] & RNG);
			if (j < n) dp[j + 1] |= tmp;
			dp[j] |= (tmp << 1);
		}
	}
	int ans = 0;
	for (int i = 0; i <= n; i++)
	{
		for (int j = 0; j <= n; j++)
		{
			if (dp[i][j]) ans = max(ans,i + j);
		}
	}
	cout << ans << '\n';
	return 0;
}