import sys

sys.setrecursionlimit(10**7)
def I(): return int(sys.stdin.readline().rstrip())
def MI(): return map(int,sys.stdin.readline().rstrip().split())
def LI(): return list(map(int,sys.stdin.readline().rstrip().split()))
def LI2(): return list(map(int,sys.stdin.readline().rstrip()))
def S(): return sys.stdin.readline().rstrip()
def LS(): return list(sys.stdin.readline().rstrip().split())
def LS2(): return list(sys.stdin.readline().rstrip())


N,L = MI()
XWT = [(0,0,0)]+[tuple(MI()) for _ in range(N)]

cur = 0
for i in range(N):
    X0,W0,T0 = XWT[i]
    X,W,T = XWT[i+1]
    cur += X-(X0+W0)
    t = cur % (2*T)
    if t+W <= T:
        cur += W
    else:
        cur += (2*T-t)+W

X0,W0,T0 = XWT[-1]
print(cur+L-(X0+W0))