class Preg():
    def __init__(self):
        self.data = "{'type'='preg', 'value'='%s', 'number'='%d', 'total'='%d'}"
        self.preg=[]
        self.cur_preg=0

    def add(self,val):
        self.preg.append(val)

    def clean(self):
        self.preg=[]

    def cur(self):
        return ( self.data % (self.preg[self.cur_preg], self.cur_preg+1, len(self.preg)))

    def prev(self):
        self.cur_preg=max(self.cur_preg-1, 0)
        return self.cur()

    def next(self):
        self.cur_preg=min(self.cur_preg+1, len(self.preg)-1)
        return self.cur()