import bisect

INF = 10 ** 17

N, M = map(int, input().split())
L = list(map(int, input().split()))
Li = []
Li.append(-INF)
for x in L:
    Li.append(x)
Li.append(INF)
ans = 0
for i in range(M):
    F, B, W = map(int, input().split())
    idx = bisect.bisect_left(Li, F)
    min_dist = abs(F - Li[idx])
    idx -= 1
    min_dist = min(min_dist, abs(F - Li[idx]))
    if min_dist < W - B:
        ans += W - min_dist
    else:
        ans += B
print(ans)