B"Hossam makes a big party, and he will invite his friends to the party. He has n friends numbered from 1 to n . They will be arranged in a queue as follows: 1, 2, 3, ldots, n . Hossam has a list of m pairs of his friends that don't know each other. Any pair not present in this list are friends. A subsegment of the queue starting from the friend a and ending at the friend b is [a, a + 1, a + 2, ldots, b] . A subsegment of the queue is called good when all pairs of that segment are friends. Hossam wants to know how many pairs (a, b) there are ( 1 <= a <= b <= n ), such that the subsegment starting from the friend a and ending at the friend b is good. The input consists of multiple test cases. The first line contains a single integer t ( 1 <= t <= 2 cdot 10^4 ), the number of test cases. Description of the test cases follows. The first line of each test case contains two integer numbers n and m ( 2 <= n <= 10^5 , 0 <= m <= 10^5 ) representing the number of friends and the number of pairs, respectively. The i -th of the next m lines contains two integers x_i and y_i ( 1 <= x_i, y_i <= n , x_i neq y_i ) representing a pair of Hossam's friends that don't know each other. Note that pairs can be repeated. It is guaranteed that the sum of n over all test cases does not exceed 10^5 , and the sum of m over all test cases does not exceed 10^5 . For each test case print an integer -- the number of good subsegments. In the first example, the answer is 4 . The good subsegments are: [1] [2] [3] [1, 2] In the second example, the answer is 5 . The good subsegments are: [1] [2] [3] [4] [3, 4] "...