# 一番近い水までの距離を見て一匹ずつどうするか決めればいいか
# bisect 

N, M = map(int, input().split())
INF = 10**20
L = [-INF]+list(map(int, input().split()))+[INF]

from bisect import *
ans = 0
for i in range(M):
    f, b, w = map(int, input().split())
    lower = L[bisect_left(L, f)-1]
    higher = L[bisect_left(L, f)]
    d = min(higher-f, f-lower)
    if d == 0:
        calc = w
    else:
        calc = max(b, w-d)
    ans += calc
    #print(f, lower, higher, d, calc)
print(ans)