from collections import defaultdict, deque, Counter
from heapq import heappop, heappush
from bisect import bisect_left, bisect_right
from math import gcd

n,m = map(int,input().split())
l = list(map(int,input().split()))
ans=0
for _ in range(m):
    f,b,w = map(int,input().split())
    idx=bisect_left(l,f)
    if idx == 0:
        ans+=max(w-(l[idx]-f), b)
    elif idx < n:
        if abs(l[idx-1]-f) < abs(l[idx]-f):
            ans+=max(w-(l[idx-1]-f), b)
        else:
            ans+=max(w-(l[idx]-f), b)
    else:
        ans+=max(w-(f-l[-1]),b)
print(ans)