#!/usr/bin/env python3

import collections


Intersection = collections.namedtuple("Intersection", "start width delta")


def compute_time(num_is, intersections):
    t = intersections[0].start
    for i in range(num_is):
        inti = intersections[i]
        if t % (2 * inti.delta) > inti.delta - inti.width:
            t += 2 * inti.delta - (t % (2 * inti.delta))
        t += intersections[i + 1].start - inti.start
    return t


def main():
    num_is, dist = map(int, input().split())
    intersections = [Intersection(*map(int, input().split()))
                     for _ in range(num_is)]
    intersections.append(Intersection(dist, 0, 0))
    print(compute_time(num_is, intersections))


if __name__ == '__main__':
    main()