CPP

how to declare comparator for set of pair

// custom comparator for set< pair<int,int> > 
struct comp {
	// operator() overloading    
    bool operator() (const pair<int, int>&a, const pair<int, int>&b){
        if((a.second - a.first)  > (b.second - b.first)){
            return true;
        }
        else if(a.second - a.first == b.second - b.first){
            return a.first < b.first;
        }
        return false;
    }
};

// declaration of set
set<pair<int, int>, comp> s;