package main

import . "fmt"
import . "os"
import bf "bufio"
import . "sort"

func main() {
	rd := bf.NewReader(Stdin)
	var n, m int
	Fscan(rd,&n,&m)
	ls := make([]int, n)
	for i := range ls {
		Fscan(rd,&ls[i])
	}
	var ans int
	for i := 0; i < m; i++ {
		var f,b,w int
		Fscan(rd,&f,&b,&w)
		j := min(n-1, SearchInts(ls, f))
		tmp := b
		for d := j-1; d <= j+1; d++ {
			if 0 <= d && d < len(ls) {
				if ls[d] == f {
					tmp = w
				} else {
					tmp = max(tmp, w-max(ls[d]-f,f-ls[d]))
				}
			}
		}
		ans += tmp
	}
	Println(ans)
}