unordered map of pair and int

1struct HASH{
2  size_t operator()(const pair<int,int>&x)const{
3    return hash<long long>()(((long long)x.first)^(((long long)x.second)<<32));
4  }
5};
6unordered_map<pair<int,int>,int,HASH>mp;
7//In Function pass it as
8
9int foo(unordered_map<pair<int,int>,int,HASH> &mp);