1 1 2 2
1000000000 1000000000
1
 1 1 1000000000 1000000000
100 1000000000
1
 1 1 10 18
5 6
5
 2 1 1000000000 2000000000
111 999999999
101 999999998
1
 4 13 400 600
13 30
1 19
1 160
1 113
58 73 15 319 194 362 128 157 336 162 77 90 96
 1 15 100 200
283 8
30 58 16 45 80 82 55 95 24 23 86 28 51 47 20
 3 2 300 400
24 68
13 65
15 113
127 177
 1 1 2 1
1 10
1
 4 2 7 15
10 9
4 4
9 3
4 10
1 6
 2 1 1000000000 2000000000
111 1000000000
101 1000000000
5
 2 1 1000000000 2000000000
111 999999998
101 999999998
1
 1 1 1000000000 1000000000
1 1000000000
1

1000000000
 -1
 5
 111
 1
 -1
 -1
 -1
 4
 101
 -1
 -1

#include <iostream>
#include <cstdio>
#include <stdlib.h>
#include <vector>
#include <climits>
#include <algorithm>
int carnum,gasnum,rdlength,time;
int *price, *total, *location;
bool check(int);
int BS(int l, int r)
{
    while(l != r)
    {
        int mid = (l+r) / 2;
        if(check(mid)) r = mid;
        else l = mid + 1;
    }
    return r;
}
bool check(int tank)
{
    long long xtime = 0;
    for(int i = 0; i < gasnum+1; i++)
    {
        long long diff = location[i+1] - location[i];
        if(2 * diff <= tank) xtime = xtime + diff;
        else if (diff <= tank) xtime = xtime + 3 * diff - tank;
        else return false;
    }
    if(xtime <= time) return true;
    else return false;
}
int main(int argc, char *argv[]) {
	scanf("%d %d %d %d",&carnum,&gasnum,&rdlength,&time);
	price = new int[carnum];
	total = new int[carnum];
	for(int i = 0; i < carnum; i++) scanf("%d %d",&price[i],&total[i]);
	location = new int[gasnum+2];
	location[0] = 0;
	for(int i = 1; i <= gasnum; i++) scanf("%d",&location[i]);
	location[gasnum+1] = rdlength;
	std::sort(location, location+gasnum+2);
	int min_size = BS(1,1000000000);
	int min_price = INT_MAX;
	for(int i = 0; i < carnum; i++)
    {
        if(total[i] >= min_size)
        {
            if(price[i] < min_price)
            {
                min_price = price[i];
            }
        }
    }
    if (min_price < INT_MAX) {
        std::cout << min_price << "\n";
    }
    else {
        std::cout << "-1\n";
    }
}