from bisect import bisect_left

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:
    b = bisect_left(L, F)
    if b < N and L[b] == F:
        ans += W
        continue
    MAX = B
    if 1 <= b:
        MAX = max(MAX, W-(F-L[b-1]))
    if b < N:
        MAX = max(MAX, W-(L[b]-F))
    ans += MAX

print(ans)