B'Allyn is playing a new strategy game called "Accumulator Apex". In this game, Allyn is given the initial value of an integer x , referred to as the accumulator, and k lists of integers. Allyn can make multiple turns. On each turn, Allyn can withdraw the leftmost element from any non-empty list and add it to the accumulator x if the resulting x is non-negative. Allyn can end the game at any moment. The goal of the game is to get the largest possible value of the accumulator x . Please help Allyn find the largest possible value of the accumulator x they can get in this game. The first line of the input contains two integers x and k ( 0 <= q x <= q 10^9, 1 <= q k <= q 10^5 ) -- the initial value of the accumulator x and the number of lists. The next k lines contain the description of lists: an integer l_i ( l_i ge 1 ) followed on the same line by l_i elements of the list in the order from left to right. Each element of lists does not exceed 10^9 by the absolute value, and the total size of all lists does not exceed 10^5 . The sole line of the output should contain the largest value of the accumulator x Allyn can get. In the first input, we start with x = 1 . Then, we can take the first integer from the first list and get x = 0 -- adding the next integer 2 from the first list we get x = 2 . After that, we can add the integers from the second list and obtain x = 3 . Finally, we can add the integers from the third list and obtain x = 4 . In the second input, we can add the first integer from the second list and get x = 2 . Then, by adding the elements from the first list, we get x = 4 . We cannot add more integers to increase x . '...