n,m = map(int,input().split())
L = [-10**10]+list(map(int,input().split()))+[10**10]

FBW = [list(map(int,input().split())) for i in range(m)]

FBW.sort()

ans = 0

now = 0
for f,b,w in FBW:
    while now < n+2 and L[now] < f:
        now += 1
    
    dist = min(f-L[now-1],L[now]-f)
    ans += max(w-dist,b)
print(ans)