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=[int(i) for i in input().split()]
cars=[]
l=1200000000
r=0
for i in range(n):
    cars.append([int(i) for i in input().split()])
g=[int(i) for i in input().split()]
g.append(s)
g.sort()
maxG=g[0]
for i in range(1,k+1):
    g[i]-=g[i-1]
    if g[i]>maxG: maxG=g[i]
while l+1<r:
    dif=(l+r)//2
    if dif<maxG:
        l=dif
        continue
    time=0
    for i in g:
        time+=i*2-min((dif-i),i)
    if time<=t:
        r=dif
    else:
        l=dif
minC=2000000000
for i in range(0,n):
    if cars[i][1]>=r:
        if cars[i][0]<minC:
            minC=cars[i][0]
if minC>=1200000000:
    print(-1)
else: print(minC)