n = int(input())
node2con = dict()
con_data = dict()
con_num = 0
clear = True
for _ in range(n):
    r0, c0, r1, c1 = map(int, input().split())
    if not clear: continue
    is_0 = (r0, c0) in node2con
    is_1 = (r1, c1) in node2con
    con0 = node2con[r0, c0] if is_0 else None
    con1 = node2con[r1, c1] if is_1 else None
    if is_0 and is_1:
        if con0 == con1:
            if con_data[con0]['roop']:
                clear = False
            else:
                con_data[con0]['roop'] = True
        else:
            for node in con_data[con1]['node']:
                node2con[node] = con0
    elif is_0 and not is_1:
        node2con[r1, c1] = con0
        con_data[con0]['node'].append((r0, c0))
    elif is_1 and not is_0:
        node2con[r0, c0] = con1
        con_data[con1]['node'].append((r1, c1))
    else:
        node2con[r0, c0] = node2con[r1, c1] = con_num
        con_data[con_num] = {'node': [(r0, c0), (r1, c1)], 'roop': False}
        con_num += 1
print(['NO', 'YES'][clear])