A = list(input())
B = list(input())

cn = 0

for i in range(len(B)):
	for j in range(cn, len(A)):
		if A[j] == B[i]:
			tmp = A[i]
			A[i] = A[j]
			A[j] = tmp
			cn += 1
			break

if A != B:
	print("NO")
else:
	print("YES")