N,S,T,K = list(map(int,input().split()))
S -= 1;T -= 1
A = list(map(int,input().split())) + [10**18]
AS = A[S]
AT = A[T]
A.remove(AS)
A.remove(AT)

MIN = min(A)
if(AS + AT <= K):
    print(1)
elif(MIN + AT <= K and AS + MIN <= K):
    print(2)
else:
    print(-1)