pair first ascending second descending

typedef struct Comp{
    bool operator()(const pair<int,int>&a, const pair<int,int>&b){
        if(a.f != b.f){
            return a.f<b.f;
        }
        return a.s>b.s;
    }
};

pair<int,int>p[MAX];

Comp c;
sort(p,p+(MAX-1),c);