There are

railway stations lying on a straight line, numbered from

to

. A strange thing is, each railway station only opens for a continuous period of time

every day. In other words, if a train arrives before time

or after time

, it can not stop at station

.
Many trains travel through these stations every day. It takes

times for each train to travel from station

to station

with the top speed.
If a train driver wants to stop at station

where the train may arrive early, he can choose to run slowly to meet the time requirements of that station. However, there is no way out if the train arrives late even with the top speed.
A new day is coming. As a train driver, now your train is at station

, plan to leave for station

at time

, and stop at all stations of

along the railway line. You are wondering whether your train can meet the arrival time requirements of all railway stations from

to

(boarding and alighting time at each station are ignored).

days are coming, one of the following three events will happen every day.
- Ask whether you can stop the train among each station
. - The railway line between station
and station
has been repaired and the passing time is changed to
. i.e., set
. - Station
change its open time to
. i.e., set
.
Please answer each question of the first type.