import bisect
def main():
	n,m=map(int,input().split())
	ls=list(map(int,input().split()))
	ans = 0
	for i in range(m):
		f,b,w=map(int,input().split())

		idx = bisect.bisect(ls,f)
		
		cost = 10**10
		if idx < n:
			cost1 = abs(f-ls[idx])
			if cost1 < cost:
				cost = cost1
		if 0 <= idx-1:
			cost2 = abs(f-ls[idx-1])
			if cost2 < cost:
				cost = cost2
		if cost < w-b:
			ans += w - cost
		else:
			ans += b
	print(ans)

if __name__ == "__main__":
	main()