import bisect

n, m = map(int, input().split())
L = list(map(int, input().split()))
F = []
B = []
W = []

for _ in range(m):
  li = list(map(int, input().split()))
  F.append(li[0])
  B.append(li[1])
  W.append(li[2])

total_cost = 0
is_move = [False]*m
for i in range(m):
  ind_1 = bisect.bisect_left(L, F[i])
  if ind_1>0 and ind_1 < n:
    ind_2 = ind_1 - 1
    cost = min(abs(F[i]-L[ind_1]), abs(F[i]-L[ind_2]))
    if cost < (W[i]-B[i]) :
      is_move[i] = True
      total_cost += cost
    else:
      continue
  elif ind_1 == 0:
    cost = abs(F[i]-L[ind_1])
    if cost < (W[i]-B[i]) :
      is_move[i] = True
      total_cost += cost
  elif ind_1 == n:
    cost = abs(F[i]-L[ind_1-1])
    if cost < (W[i]-B[i]) :
      is_move[i] = True
      total_cost += cost
      
total_score = 0
for j in range(m):
  if is_move[j]:
    total_score += W[j]
  else:
    total_score += B[j]

total_score -= total_cost
print(total_score)