# Monk And Some Queries

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#
#   Monk was asked to answer some queries in an interview. He is given an empty array A. Queries are of 4 types:-
#   1. 1 X - Add number X to the array A.
#   2. 2 X - Remove a single instance of number X from the array A. If not possible, print "-1" without the quotes.
#   3. 3 - Find the maximum element in the array A.
#   4. 4 - Find the minimum element in the array A.
#
#   Input:
#   The first line contains the integer Q.
#   The next Q lines will each contain a query like the ones mentioned above.
#
#   Output:
#   For queries 3 and 4, print the answer in a new line. If the array is empty for query 3 and 4,
#   then print "-1" without the quotes.
#
#   Constraints:
#   1 <= Q <= 100000
#   1 <= X <= 100000
#
#   SAMPLE INPUT
#   5
#   1 5
#   1 9
#   1 6
#   3
#   2 1
#
#   SAMPLE OUTPUT
#   9
#   -1
#
#   Explanation
#   There are 5 queries.
#   Query 1 - 5 is added to the array.
#   Query 2 - 9 is added to the array.
#   Query 3 - 6 is added to the array.
#   Query 4 - The maximum element in the array is 9.
#   Query 5 - Since there is no element in the array with value 1, so the output is -1.
#
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