B"You are in a corridor that extends infinitely to the right, divided into square rooms. You start in room 1 , proceed to room k , and then return to room 1 . You can choose the value of k . Moving to an adjacent room takes 1 second. Additionally, there are n traps in the corridor: the i -th trap is located in room d_i and will be activated s_i seconds after you enter the room boldsymbol{d_i} . Once a trap is activated, you cannot enter or exit a room with that trap. Determine the maximum value of k that allows you to travel from room 1 to room k and then return to room 1 safely. For instance, if n=1 and d_1=2, s_1=2 , you can proceed to room k=2 and return safely (the trap will activate at the moment 1+s_1=1+2=3 , it can't prevent you to return back). But if you attempt to reach room k=3 , the trap will activate at the moment 1+s_1=1+2=3 , preventing your return (you would attempt to enter room 2 on your way back at second 3 , but the activated trap would block you). Any larger value for k is also not feasible. Thus, the answer is k=2 . The first line of the input contains an integer t ( 1 <= t <= 1000 ) -- the number of test cases. The descriptions of the test cases follow. The first line of each test case description contains an integer n ( 1 <= n <= 100 ) -- the number of traps. The following n lines of each test case description present two integers d_i and s_i ( 1 <= d_i, s_i <= 200 ) -- the parameters of a trap (you must leave room d_i strictly before s_i seconds have passed since entering this room). It's possible for multiple traps to occupy a single room (the values of d_i can be repeated). For each test case, print the maximum value of k that allows you to travel to room k and return to room 1 without encountering an active trap"...