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=input().split()
price=[]
litraj=[]
price_new=[]
time=0
times=[]
k=int(n[1])
s=int(n[2])
t=int(n[3])
n=int(n[0])
for i in range(n):
    temp=input().split()
    price.append(int(temp[0]))
    litraj.append(int(temp[1]))
zap=input().split()
zap.append(str(s))
zap=sorted([int(j) for j in zap])
prev_zap=0
for litr in litraj:
    rast=0
    prev_zap=0
    time=0
    for zapr in zap:
        rast=zapr-prev_zap
        prev_zap=zapr
        for i in range(rast):
            if i*2+rast-i<=litr:
                uskr=i
        time+=uskr+(rast-uskr)*2
        if uskr==0 and rast>litr:
            time=-1
    times.append(time-1)
min_t=times[0]
for i in range(len(times)):
    if times[i]<=t and times[i]!=-1:
        price_new.append(price[i])
print(min(price_new))



