import java.io.*;
import java.util.*;
public class snowboots {
    static int n,k;
    static int[] field,a,b; //a,b --> strength, distance
    static int pos;
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new FileReader("snowboots.in"));
        PrintWriter pw = new PrintWriter(new BufferedWriter(new FileWriter("snowboots.out")));
        StringTokenizer st = new StringTokenizer(br.readLine());
        n = Integer.parseInt(st.nextToken());
        k = Integer.parseInt(st.nextToken());
        st = new StringTokenizer(br.readLine());
        field = new int[n];
        a = new int[k];
        b = new int[k];
        for (int i = 0; i < n; i++)
            field[i] = Integer.parseInt(st.nextToken());
        for (int i = 0; i < k; i++) {
            st = new StringTokenizer(br.readLine());
            a[i] = Integer.parseInt(st.nextToken());
            b[i] = Integer.parseInt(st.nextToken());
        }

        pw.println(solve());
        pw.close();

    }
    static int solve() {
        pos = 0;
        int i = 0; //which boot are we on?
        while(pos < n-1) {

            while(move(i)); //move with boot i as far as possible

            i++; //use the next boot

        }
        i--;
        return i;
    }
    static boolean move(int c) {
        for (int i = pos+b[c]; i > pos; i--) {
            if (i < n && field[i] <= a[c]) { //snow has to be less than boot strength
                pos = i;
                return true;
            }
        }
        return false;
    }
}