def removeOne(st):
    foundGood = False
    i = len(st)-1
    while(i>0):
        if(st[i]=='}' and st[i-1]=='{'):
            st=st[0:i-1]+(st[i+1:] if(i!=len(st)-1) else '')
            foundGood = True
        else:
            if(st[i]==')' and st[i-1]=='('):
                st=st[0:i-1]+(st[i+1:] if(i!=len(st)-1) else '')
                foundGood = True
            else:
                if(st[i]==']' and st[i-1]=='['):
                    st=st[0:i-1]+(st[i+1:] if(i!=len(st)-1) else '')
                    foundGood = True
        if(i>len(st)-1):
            i=len(st) - 1
        else:
            i-=1
    if(foundGood):
        return st
    else:
        return '0'

sk = str(input())

while(sk!='0' and sk!=''):
    sk=removeOne(sk)
if(sk==''):
    print('yes')
else:
    print('no')