package pickpocket;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Scanner;

public class pickpockets {
	public static void main(String[] args) throws IOException {
	String tmp;
	String tmpstr[] = new String[2];
	int days = 0, numOfTeams = 0, sum = 0;
	List<int[]> operations = new ArrayList<int[]>();
	BufferedReader reader = new BufferedReader(
            new InputStreamReader(System.in));
	
	tmp = reader.readLine();
	tmpstr = tmp.split(" ", 2);
	days = Integer.parseInt(tmpstr[0]);
	int numOfCleanStores [] = new int  [days];
	numOfTeams = Integer.parseInt(tmpstr[1]);
	tmp = reader.readLine();
	tmpstr = tmp.split(" ", -1);
	for(int i = 0; i < days; i++) {
		numOfCleanStores[i] = Integer.parseInt(tmpstr[i]);
	}
	while((tmp = reader.readLine()) != null) {
		tmpstr = tmp.split(" ");
		int [] tmpint = {Integer.parseInt(tmpstr[0]), Integer.parseInt(tmpstr[1])};
		operations.add(tmpint);
	}
	
	for(int i = 0; i < days; i++) {
		for(int[] list: operations) {
			if(list[0] == days - i) {
				if(numOfCleanStores[0] >= 1) {
					sum += list[1];
					operations.remove(list);
					numOfCleanStores[0] -= 1;
				}
			}
		}
	}
	
	System.out.println(sum);
	
}
}