Count number of equal pairs in a string - GFG

class Solution
{
  public:
    long long int equalPairs (string s)
    {
    	//code here.
    	unordered_map <char,int> m;
    	for(int i=0;i<s.size();i++)
    	{
    	    m[s[i]]++;
    	}
    	int count=0;
    	for(auto pair: m)
    	{
    	    count+=(pow((pair.second),2));
    	}
    	return count;
    }
};