L=[]
while True:
    big=0
    small=0
    a=input()
    var=True
    if (a=='.'):
        break
    else:
        temp=[]
        var=True
        for x in a:
            if x=='[':
                big+=1
                temp.append(x)
            elif x==']':
                big-=1
                temp.append(x)
            elif x=='(':
                small+=1
                temp.append(x)
            elif x==')':
                small-=1
                temp.append(x)
            if big<0 or small<0:
                var=False
                break
    for k in range(len(temp)-1):
        if( temp[k]=='(' and temp[k+1]==']') or ( temp[k]=='[' and temp[k+1]==')'):
            var=False
    if big==0 and small==0 and var==True:
        L.append('yes')
    else:
        L.append('no')    
for i in L:
    print(i)

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

W1soKFtdKV0pXQou

[[(([])])]
.