import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.AbstractMap;
import java.util.TreeMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import java.util.InputMismatchException;
import java.io.IOException;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        FastReader in = new FastReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        DIntegerCards solver = new DIntegerCards();
        solver.solve(1, in, out);
        out.close();
    }

    static class DIntegerCards {
        public void solve(int testNumber, FastReader s, PrintWriter out) {
            int n = s.nextInt();
            int m = s.nextInt();
            long[] arr = s.nextLongArray(n);
            TreeMap<Long, Integer> map = new TreeMap<>();
//        long sum = 0;
            for (int i = 0; i < n; i++) {
                map.put(arr[i], map.getOrDefault(arr[i], 0) + 1);
//            sum += arr[i];
            }


            for (int i = 0; i < m; i++) {
                int b = s.nextInt();
                long c = s.nextLong();
                Long lower = map.lowerKey(c);
                int freq = b;

                while (!map.isEmpty() && freq > 0) {
                    Long e = map.firstEntry().getKey();
                    if (e > c) {
                        break;
                    }
                    int v = map.get(e);
                    if (v > freq) {
                        v -= freq;
                        freq = 0;
                        map.put(e, v);
                    } else {
                        map.pollFirstEntry();
                        freq -= v;
                    }
                }


                if (freq != b) {
                    map.put(c, b - freq + map.getOrDefault(c, 0));
                }
            }
//        out.println(map);
            Iterator<Long> keys = map.keySet().iterator();
            long sum = 0;
            while (keys.hasNext()) {
                long key = keys.next();
                sum += (long) (map.get(key)) * key;
            }
            out.println(sum);
        }

    }

    static class FastReader {
        private InputStream stream;
        private byte[] buf = new byte[1024];
        private int curChar;
        private int numChars;
        private FastReader.SpaceCharFilter filter;

        public FastReader(InputStream stream) {
            this.stream = stream;
        }

        public int read() {
            if (numChars == -1) {
                throw new InputMismatchException();
            }
            if (curChar >= numChars) {
                curChar = 0;
                try {
                    numChars = stream.read(buf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
                if (numChars <= 0) {
                    return -1;
                }
            }
            return buf[curChar++];
        }

        public int nextInt() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = read();
            }
            int res = 0;
            do {
                if (c < '0' || c > '9') {
                    throw new InputMismatchException();
                }
                res *= 10;
                res += c - '0';
                c = read();
            } while (!isSpaceChar(c));
            return res * sgn;
        }

        public long nextLong() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = read();
            }
            long res = 0;
            do {
                if (c < '0' || c > '9') {
                    throw new InputMismatchException();
                }
                res *= 10;
                res += c - '0';
                c = read();
            } while (!isSpaceChar(c));
            return res * sgn;
        }

        public boolean isSpaceChar(int c) {
            if (filter != null) {
                return filter.isSpaceChar(c);
            }
            return isWhitespace(c);
        }

        public static boolean isWhitespace(int c) {
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }

        public long[] nextLongArray(int n) {
            long[] array = new long[n];
            for (int i = 0; i < n; ++i) array[i] = nextLong();
            return array;
        }

        public interface SpaceCharFilter {
            public boolean isSpaceChar(int ch);

        }

    }
}



Measured memory_bytes: 50944