Howard has recently started a new full-time job which gives him vacation days to use during the year. He is looking to spend all of his vacation days on a single trip to Hanoi, however he is having a hard time finding a pair of flights that are exactly days apart.
Given the flights to and from Hanoi this year, find the minimum cost of two flights and such that:
- is a flight to Hanoi.
- is a flight from Hanoi.
- and are exactly days apart.
The first line of input contains two integers , the number of flights and the number of vacation days that Howard has.
The next lines each contain three terms describing a flight, where:
- is the day the flight departs.
- is either
F, representing whether the flight is to or from Hanoi, respectively.
- is the cost of the flight.
Output the minimum cost of a pair of flights satisfying the conditions in the problem description, or
-1 if no such pair exists.
Sample Input 1
2 3 1 F 1000 4 T 1000
Sample Output 1
Sample Input 2
3 5 1 T 1000 3 T 100 6 F 1000
Sample Output 2