class Solution
{
    public:
    long long countKdivPairs(int A[], int n, int K)
    {
        //code here
        long ans=0;
        unordered_map<int,int>m;
        for(int i=0;i<n;i++)
        {
            int rem=A[i]%K;
            if(rem!=0)
            {
                ans+=m[K-rem];
            }
            else ans+=m[0];
            m[rem]++;
        }
        return ans;
    }
};