#############################################################

import sys
sys.setrecursionlimit(10**7)

from heapq import heappop,heappush
from collections import deque,defaultdict,Counter
from bisect import bisect_left, bisect_right
from itertools import product,combinations,permutations
from math import sin,cos
#from math import isqrt #DO NOT USE PyPy

ipt = sys.stdin.readline
iin = lambda :int(ipt())
lmin = lambda :list(map(int,ipt().split()))

#############################################################

N,M = lmin()
L = lmin()

ans = 0
for _ in range(M):
    F,B,W = lmin()
    t = B
    idx = bisect_left(L,F)
    if idx != 0:
        t = max(t,W-abs(F-L[idx-1]))
    if idx != N:
        t = max(t,W-abs(F-L[idx]))
    ans += t
print(ans)