import std.algorithm;
import std.array;
import std.ascii;
import std.container;
import std.conv;
import std.math;
import std.numeric;
import std.range;
import std.stdio;
import std.string;
import std.typecons;
void log(A...)(A arg) { stderr.writeln(arg); }
int size(T)(in T s) { return cast(int)s.length; }

const int[] dy = [-1, 0, 1, 0];
const int[] dx = [0, 1, 0, -1];

struct Point {
    int y, x;
}
const Z = 120;

void main() {
    int N; readf("%d\n", &N);
    Point[][Point] G;
    foreach (i; 0 .. N) {
        int sy, sx, gy, gx;
        readf("%d %d %d %d\n", &sy, &sx, &gy, &gx);
        G[Point(sy, sx)] ~= Point(gy, gx);
        G[Point(gy, gx)] ~= Point(sy, sx);
    }

    bool[Point] used;
    bool dfs(in Point p, in Point prev) {
        if (p in used) {
            // 繧ゅ←縺｣縺ｦ譚･縺溘ｉ縲∵悴菴ｿ逕ｨ縺ｮ霎ｺ縺梧ｮ九▲縺ｦ縺・ｌ縺ｰ繧｢繧ｦ繝医€∵ｮ九▲縺ｦ縺・↑縺代ｌ縺ｰ繧ｻ繝ｼ繝・////
            foreach (next; G[p]) {
                if (next == prev) continue;
                if (next !in used) return false;
            }
            return true;
        }

        used[p] = true;
        foreach (next; G[p]) {
            if (next == prev) continue;
            if (! dfs(next, p)) return false;
        }
        return true;
    }

    foreach (int y; 0 .. Z) {
        foreach (int x; 0 .. Z) {
            if (Point(y, x) !in G) continue;
            used.clear();
            if (! dfs(Point(y, x), Point(-1, -1))) {
                writeln("NO");
                return;
            }
        }
    }
    writeln("YES");

}