from collections import *
import heapq
import bisect

INF = float("inf")

N, M = map(int, input().split())
L = [-INF] + list(map(int, input().split())) + [INF]
ans = 0
for _ in range(M):
    F, B, W = map(int, input().split())
    pl = bisect.bisect_left(L, F)
    ans += max(B, W - min(L[pl] - F, F - L[pl - 1]))
    # print(F, B, W - min(L[pl] - F, F - L[pl - 1]))
print(ans)