//  [java]
import java.util.*;
import java.io.*;
class Main{
    public static void main(String[] args){
        FastScanner fs = new FastScanner();
        int n = fs.nextInt();
        int m = fs.nextInt();
        int[] a = new int[n];
        long sum = 0;
        for(int i=0;i<n;i++){
            a[i] = fs.nextInt();
            sum+=a[i];
        }
        Arrays.sort(a);
        int[][] bc = new int[m][2];
        for(int i=0;i<m;i++){
            bc[i][0] = fs.nextInt();
            bc[i][1] = fs.nextInt();
        }
        Arrays.sort(bc,new Comparator<int[]>(){
          @Override
          public int compare(int[] o1,int[] o2){
            return o2[1]-o1[1];
          }
        });
        int idx = 0;
        
        for(int i=0;i<m;i++){
            if(a[idx] >= bc[i][1])break;
            int count = bc[i][0];
            int num = bc[i][1];
            for(int j=0;j<count && idx < n;j++){
                if(a[idx] >=num )break;
                sum-=a[idx];
                sum+=num;
                idx++;
            }
            if(idx == n){
                break;
            }
        }
        System.out.println(sum);

    }
    static class FastScanner{
        private final InputStream in = System.in;
        private final byte[] buffer = new byte[1024];
        private int ptr = 0;
        private int buflen = 0;

        private boolean hasNextByte(){
            if(ptr < buflen){
                return true;
            }else{
                ptr = 0;
                try{
                    buflen = in.read(buffer);
                }catch(IOException e){
                    e.printStackTrace();
                }
                if(buflen <= 0){
                    return false;
                }
            }
            return true;
        }

        private int readByte(){
            if(hasNextByte())return buffer[ptr++];
            else return -1;
        }

        private boolean isPrintableChar(int c){
            return 33<=c && c<=126;
        }

        public boolean hasNext(){
            while(hasNextByte() && !isPrintableChar(buffer[ptr]))ptr++;
            return hasNextByte();
        }

        public String next(){
            if(!hasNext()) throw new NoSuchElementException();
            StringBuilder sb = new StringBuilder();
            int b = readByte();
            while(isPrintableChar(b)){
                sb.appendCodePoint(b);
                b = readByte();
            }
            return sb.toString();
        }

        public long nextLong(){
            if(!hasNext()) throw new NoSuchElementException();
            long n = 0;
            boolean minus = false;
            int b = readByte();
            if(b == '-'){
                minus = true;
                b = readByte();
            }
            if(b < '0' || '9' < b){
                throw new NumberFormatException();
            }
            while(true){
                if('0' <= b && b<='9'){
                    n*=10;
                    n+=b-'0';
                }else if(b==-1 || !isPrintableChar(b)){
                    return minus ? -n : n;
                }else{
                    throw new NumberFormatException();
                }
                b = readByte();
            }
        }
        public int nextInt(){
            long nl = nextLong();
            if(nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE)throw new NumberFormatException();
            return (int)nl;
        }
        public double nextDouble(){return Double.parseDouble(next());}
    }
}