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,ta=map(int,input().split())
mi=-1
c=[0]*n; v=[0]*n
for i in range (n):
    c[i],v[i]=map(int,input().split())
z=list(map(int,input().split()))
z.append(s)
for i in range(n):
    t=0
    p=0
    for b in z:
        dl=b-p
        if dl<=v[i]/2:
            t+=dl
        elif dl>v[i]:
            break
        else:
            t+=3*dl-v[i]
        p=b
    if t<=ta and (c[i]<mi or mi==-1):
        mi=c[i]
print(mi)   
        
            
        
        
