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())
    k = bisect_left(L, F)
    res = B
    if k > 0:
        res = max(res, W-(F-L[k-1]))
    if k < N:
        res = max(res, W-(L[k]-F))
    ans += res

print(ans)