from itertools import product

if __name__ == '__main__':
    k, n = map(int, input().strip().split())

    arrays = []

    for _ in range(1, k + 1):
        arr = list(input().strip().split())[1:]
        arrays.append(arr)

    s_max = 0

    for combo in product(*arrays):
        sum_combo = sum(int(x) ** 2 for x in combo)
        current_s_max = sum_combo % n
        s_max = max(current_s_max, s_max)

    print(s_max)