2244. Minimum Rounds to Complete All Tasks

class Solution(object):
    def minimumRounds(self, tasks):
        dict1={}
        ans=0
        for i in tasks:
            if i in dict1:
                dict1[i]+=1
            else:
                dict1[i]=1
        for i in dict1:
            while dict1[i]!=0:
                if dict1[i]==1:
                    return -1
                if dict1[i]%3==0:
                    ans+=dict1[i]//3
                    dict1[i]%=3
                else:
                    ans+=1
                    dict1[i]-=2
        return ans