import sys
input = sys.stdin.readline

from bisect import bisect

N,M=map(int,input().split())

L=list(map(int,input().split()))

ANS=0

for i in range(M):
    x,y,z=map(int,input().split())

    PLUS=y

    k=bisect(L,x)

    for j in range(max(0,k-2),min(len(L),k+2)):
        PLUS=max(PLUS,z-abs(x-L[j]))

    ANS+=PLUS
print(ANS)