Comparator function for SET

#include <bits/stdc++.h>
using namespace std;
#define f first
#define s second
typedef pair < int, int > p;
#define A(v)  v.begin(), v.end()
class comp{
    public:
    bool operator ()(const p &a, const p &b) const{
        if(a.f == b.f)return a.s > b.s;
        if(a.f == 0)return 1;
        return 0;
    }
};
int main() {
    int n, i, l, r;
    cin >> n;
    multiset < p , comp> ss;
    for(int i = 0; i < n; i++){
        cin >> l >> r;
        ss.insert({l,r});
    }
    for(auto i : ss)cout << i.s << ' ';
    return 0;
}