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n=int(raw_input())
for _ in range(n):
    flg=True
    s1=raw_input().split()[0]
    s2=raw_input().split()[0]
    to = [None] * 26
    for i in range(len(s1)):
        c1=s1[i]
        c2=s2[i]
        c=ord(c1)-ord('a')
        if to[c]==None:
            to[c]=c2
            continue
        if to[c]==c2:
            continue
        if to[c]!=c2:
            flg=False
    if flg:
        print('YES')
    else:
        print('NO')
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