def happyLadybugs(b):
    #first check: no space in this string , True if they are already friends , false else
    if b.count("_")<1:
        liste=[]
        for i in b:
            if i not in liste:
                liste.append(i)
        res_list= list(map(lambda x :b.count(x)*x,liste))
        if "".join(res_list)==b:
            for i in b:
                if b.count(i)==1:
                    return "NO"
            return "YES"
        else:
            return "NO"
    #second check : if all the string is underscore     
    elif b.replace("_","")=="":
        return "YES"
    #third check : if you survived the first two , one space(underscore) should be enough to validate the happy bugs
    else:
        bug_set = set(b.replace("_",""))
        bug_string="".join(bug_set)
        for i in bug_string:
            if b.count(i)==1:
                return "NO"
        return "YES"