#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <cstring>

using namespace std;

const int MAXN=34;

int n,re[MAXN],i,j,k,w[MAXN],v[MAXN],m,A,B,tot,ans=0,s;
bool used[MAXN];

void init()
{
	freopen("rival.in","r",stdin);
	freopen("rival.out","w",stdout);
	scanf("%d%d",&A,&B);
	scanf("%d%d",&n,&m);
	for (i=1;i<=n;i++)
	{
		scanf("%d%d",&v[i],&w[i]);
		tot+=v[i];
	}
	
}

void pd()
{
	int i,tmp=0,V=0;
	for (i=1;i<=n;i++)
	{
		if (V+w[re[i]]<=A)
		{
			tmp+=v[re[i]];
			V+=w[re[i]];
		}
		else break;
	}
	V=0;
	for (;i<=n;i++)
	{
		if (V+w[re[i]]*2<=B)
		{
			tmp+=v[re[i]];
			V+=w[re[i]]*2;
		}
	}
	if (tmp>ans) 
	{
		ans=tmp;
	}
}

void dfs()
{
	if (s==n)
	{
		pd();
		return;
	}
	int i;
	for (i=1;i<=n;i++)
		if (!used[i])
		{
			re[++s]=i;
			used[i]=true;
			dfs();
			--s;
			used[i]=false;
		}
}

int main()
{
	init();
	if (n<=10)
	{
		memset(used,false,sizeof(used));
		s=0;
		dfs();
		printf("%d\n",tot-ans);
	}
	return 0;
}