from bisect import bisect_left
import sys
input = sys.stdin.readline

n, m = map(int, input().split())
L = list(map(int, input().split()))
ans = 0
for _ in range(m):
    f, b, w = map(int, input().split())
    idx = bisect_left(L, f)
    res = b
    if idx < n:
        res = max(res, w - (L[idx] - f))
    if idx > 0:
        res = max(res, w - (f - L[idx - 1]))
    ans += res
print(ans)