n,m = map(int,input().split())
l = list(map(int,input().split()))

from bisect import *

ans = 0

for i in range(m):
    f,b,w = map(int,input().split())
    ind = bisect_left(l,f)
    if ind == 0:
        if l[ind] == f:
            ans += w
        else:
            ans += max(b,w-(l[0]-f))
    elif ind == n:
        if l[n-1] == f:
            ans += w
        else:
            ans += max(b,w-(f-l[n-1]))
    else:
        if l[ind] == f:
            ans += w
        else:
            tmp1 = w-(f-l[ind-1])
            tmp2 = w-(l[ind]-f)
            ans += max(b,tmp1,tmp2)
            
print(ans)