from bisect import *

N, M = map(int, input().split())
L = list(map(int, input().split()))
FBW = [list(map(int, input().split())) for _ in range(M)]

ans = 0
for f, b, w in FBW:
    a = bisect_left(L, f)
    tmp = b
    if a > 0:
        tmp = max(tmp, w - f + L[a - 1])
    if a < N:
        tmp = max(tmp, w - L[a] + f)
    ans += tmp
print(ans)