#include <iostream>
#include <CGAL/Exact_predicates_exact_constructions_kernel.h>

typedef CGAL::Exact_predicates_exact_constructions_kernel K;
typedef K::Point_2 Point;
typedef K::Ray_2 Ray;
typedef K::Segment_2 Segment;

using namespace std;

bool oneCase(int n) {
    bool intersects = false;
    long long x,y, ex, ey; cin >> x >> y >> ex >> ey;
    Point start(x, y), end(ex, ey);
    Ray phil(start, end);
    for (int i = 0; i < n; ++i) {
        cin >> x >> y >> ex >> ey;
        Point s(x, y), e(ex, ey);
        Segment l(s, e);
        if (!intersects && CGAL::do_intersect(phil, l))
            intersects = true; // Need to read to the end
    }
    return intersects;
}

int main() {
    ios_base::sync_with_stdio(false);
    int n; cin >> n;
    while (n) {
        cout << (oneCase(n) ? "yes" : "no") << endl;
        cin >> n;
    }
    return 0;
}