$\ \ \ \ \ \ \$python大法好，拒绝手写结构体排序，从我做起（实际上是py自带的关键字排序）。

m = int(input())
for _ in range(m):
    n = int(input())
    act = []
    act_num = 1
    for __ in range(n):
        lst = list(map(int, input().split( )))
        act.append(lst)
    act.sort(key = lambda x : x[1])
    pointer = 0
    for i in range(1, n):
        if act[i][0] > act[pointer][1]:
            act_num += 1
            pointer = i
    print(act_num)