B'Let a_1, ldots, a_n be an array of n positive integers. In one operation, you can choose an index i such that a_i = i , and remove a_i from the array (after the removal, the remaining parts are concatenated). The weight of a is defined as the maximum number of elements you can remove. You must answer q independent queries (x, y) : after replacing the x first elements of a and the y last elements of a by n+1 (making them impossible to remove), what would be the weight of a ? The first line contains two integers n and q ( 1 <= n, q <= 3 cdot 10^5 ) -- the length of the array and the number of queries. The second line contains n integers a_1 , a_2 , ..., a_n ( 1 <= q a_i <= q n ) -- elements of the array. The i -th of the next q lines contains two integers x and y ( x, y ge 0 and x+y < n ). Print q lines, i -th line should contain a single integer -- the answer to the i -th query. Explanation of the first query: After making first x = 3 and last y = 1 elements impossible to remove, a becomes [ x , x , x , 9, 5, 4, 6, 5, 7, 8, 3, 11, x ] (we represent 14 as x for clarity). Here is a strategy that removes 5 elements (the element removed is colored in red): It is impossible to remove more than 5 elements, hence the weight is 5 . '...