Count Good Meals

class Solution:
    def countPairs(self, deliciousness: List[int]) -> int:
        mod=10**9 +7 
        count=Counter(deliciousness)
        maximum=max(deliciousness)
        maxi= int(log2(maximum)) + 1
        answer=0
        print(count,maxi)
        for i in count:
            for j in range(maxi+1):
                dif=2**j-i
                if dif in count and count[dif]: 
                    # print(dif)
                    if dif==i and count[dif]<=1: continue
                    elif dif==i and count[dif]>1: 
                        deno= factorial(count[i]-2)*factorial(2)
                        answer += (factorial(count[i])// deno)
                    else: 
                        answer+=(count[dif]*count[i])
            count[i]=0
            answer%=mod
        return answer%mod