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

n, k, s, t = map(int, input().split()) #auto, oil, cinema, time

auto = ["0"]  * n
for i in range(n):
    auto[i] = list(map(int, input().split()))
auto.sort()

g = [0, s]
g += list(map(int, input().split()))
g.sort()

def time(v, l):
    if v < l:
        return 10 * t
    else:
        return (v - l) + (2 * l - v) * 2

result1 = 2 * t
i = 0
while i < n and result1 > t:
    timing = 0
    for j in range(1, k + 1):
        l = g[j] - g[j - 1]
        v = auto[i][1]
        timing += time(v, l)
       
    if result1 > timing:
        result1 = timing 
    i += 1

if result1 > t:
    print(-1)
else:
    print(auto[i][0])