Problem:
Score : 700 points

Problem Statement

We have an integer sequence of length N: A_0,A_1,\cdots,A_{N-1}.

Find the following sum (\mathrm{lcm}(a, b) denotes the least common multiple of a and b):

\sum_{i=0}^{N-2} \sum_{j=i+1}^{N-1} \mathrm{lcm}(A_i,A_j)

Since the answer may be enormous, compute it modulo 998244353.

Constraints

1 \leq N \leq 200000

1 \leq A_i \leq 1000000

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N
A_0\ A_1\ \cdots\ A_{N-1}

Output

Print the sum modulo 998244353.

Sample Input 1

3
2 4 6

Sample Output 1

22

\mathrm{lcm}(2,4)+\mathrm{lcm}(2,6)+\mathrm{lcm}(4,6)=4+6+12=22.

Sample Input 2

8
1 2 3 4 6 8 12 12

Sample Output 2

313

Sample Input 3

10
356822 296174 484500 710640 518322 888250 259161 609120 592348 713644

Sample Output 3

353891724

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Time Limit Exceeded)

import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.stream.IntStream;
import java.util.Arrays;
import java.util.HashMap;
import java.util.ArrayList;
import java.nio.charset.Charset;
import java.util.StringTokenizer;
import java.util.Map;
import java.io.OutputStreamWriter;
import java.io.OutputStream;
import java.io.BufferedWriter;
import java.util.Set;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.UncheckedIOException;
import java.util.List;
import java.io.Writer;
import java.util.Map.Entry;
import java.io.BufferedReader;
import java.io.InputStream;

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

    static class CLCMs {
        private static final int MAX = 1_000_001;
        private static final int MOD = 998244353;
        private static final ModMath MM = new ModMath(MOD);
        private static final PrimeTable table = new PrimeTable(MAX);
        private static final long[] coeff = new long[MAX];

        public void solve(int testNumber, LightScanner in, LightWriter out) {
            Arrays.fill(coeff, -1);
            coeff[1] = 1;
            int n = in.ints();
            int[] a = in.ints(n);
            IntroSort.sort(a);
            int[] sum = new int[MAX];
            long ans = 0;
            for (int num : a) {
                for (int d : table.getDivisors(num)) {
                    if (sum[d] > 0) {
                        ans += sum[d] * coeff(d) % MOD * num % MOD;
                        if (ans >= MOD) ans -= MOD;
                    }
                    sum[d] += num;
                    if (sum[d] >= MOD) sum[d] -= MOD;
                }
            }
            out.ans(ans).ln();
        }

        private static long coeff(int divisor) {
            if (coeff[divisor] != -1) return coeff[divisor];
            long coefficient = 0;
            for (int d : table.getDivisors(divisor)) {
                if (d == divisor) continue;
                coefficient += coeff(d);
            }
            coefficient %= MOD;
            coefficient = (MM.inv(divisor) - coefficient + MOD) % MOD;
            return coeff[divisor] = coefficient;
        }

    }

    static interface Verified {
    }

    static class IntroSort {
        private static int INSERTIONSORT_THRESHOLD = 16;

        private IntroSort() {
        }

        static void sort(int[] a, int low, int high, int maxDepth) {
            while (high - low > INSERTIONSORT_THRESHOLD) {
                if (maxDepth-- == 0) {
                    HeapSort.sort(a, low, high);
                    return;
                }
                int cut = QuickSort.step(a, low, high);
                sort(a, cut, high, maxDepth);
                high = cut;
            }
            InsertionSort.sort(a, low, high);
        }

        public static void sort(int[] a) {
            if (a.length <= INSERTIONSORT_THRESHOLD) {
                InsertionSort.sort(a, 0, a.length);
            } else {
                sort(a, 0, a.length, 2 * BitMath.msb(a.length));
            }
        }

    }

    static class LightWriter implements AutoCloseable {
        private final Writer out;
        private boolean autoflush = false;
        private boolean breaked = true;

        public LightWriter(Writer out) {
            this.out = out;
        }

        public LightWriter(OutputStream out) {
            this(new BufferedWriter(new OutputStreamWriter(out, Charset.defaultCharset())));
        }

        public LightWriter print(char c) {
            try {
                out.write(c);
                breaked = false;
            } catch (IOException ex) {
                throw new UncheckedIOException(ex);
            }
            return this;
        }

        public LightWriter print(String s) {
            try {
                out.write(s, 0, s.length());
                breaked = false;
            } catch (IOException ex) {
                throw new UncheckedIOException(ex);
            }
            return this;
        }

        public LightWriter ans(String s) {
            if (!breaked) {
                print(' ');
            }
            return print(s);
        }

        public LightWriter ans(long l) {
            return ans(Long.toString(l));
        }

        public LightWriter ln() {
            print(System.lineSeparator());
            breaked = true;
            if (autoflush) {
                try {
                    out.flush();
                } catch (IOException ex) {
                    throw new UncheckedIOException(ex);
                }
            }
            return this;
        }

        public void close() {
            try {
                out.close();
            } catch (IOException ex) {
                throw new UncheckedIOException(ex);
            }
        }

    }

    static final class BitMath {
        private BitMath() {
        }

        public static int count(int v) {
            v = (v & 0x55555555) + ((v >> 1) & 0x55555555);
            v = (v & 0x33333333) + ((v >> 2) & 0x33333333);
            v = (v & 0x0f0f0f0f) + ((v >> 4) & 0x0f0f0f0f);
            v = (v & 0x00ff00ff) + ((v >> 8) & 0x00ff00ff);
            v = (v & 0x0000ffff) + ((v >> 16) & 0x0000ffff);
            return v;
        }

        public static int msb(int v) {
            if (v == 0) {
                throw new IllegalArgumentException("Bit not found");
            }
            v |= (v >> 1);
            v |= (v >> 2);
            v |= (v >> 4);
            v |= (v >> 8);
            v |= (v >> 16);
            return count(v) - 1;
        }

    }

    static class PrimeTable {
        private final int[] divisor;
        private final List<Integer> primes = new ArrayList<>();

        public PrimeTable(int n) {
            this.divisor = new int[n];
            for (int i = 2; i < n; i++) {
                if (divisor[i] != 0) continue;
                divisor[i] = i;
                primes.add(i);
                for (int j = i + i; j < n; j += i) {
                    if (divisor[j] == 0) divisor[j] = i;
                }
            }
        }

        public Map<Integer, Integer> primeFactorize(int x) {
            Map<Integer, Integer> res = new HashMap<>();
            while (divisor[x] != 0) {
                res.merge(divisor[x], 1, Integer::sum);
                x /= divisor[x];
            }
            return res;
        }

        public List<Integer> getDivisors(int x) {
            Set<Map.Entry<Integer, Integer>> factors = primeFactorize(x).entrySet();
            int count = 1;
            for (Map.Entry<Integer, Integer> ent : factors) count *= ent.getValue() + 1;
            List<Integer> divisors = new ArrayList<>();
            for (int i = 0; i < count; i++) {
                int t = i;
                int v = 1;
                for (Map.Entry<Integer, Integer> ent : factors) {
                    int exp = t % (ent.getValue() + 1);
                    for (int j = 0; j < exp; j++) v *= ent.getKey();
                    t /= ent.getValue() + 1;
                }
                divisors.add(v);
            }
            return divisors;
        }

    }

    static class InsertionSort {
        private InsertionSort() {
        }

        static void sort(int[] a, int low, int high) {
            for (int i = low; i < high; i++) {
                for (int j = i; j > low && a[j - 1] > a[j]; j--) {
                    ArrayUtil.swap(a, j - 1, j);
                }
            }
        }

    }

    static class LightScanner {
        private BufferedReader reader = null;
        private StringTokenizer tokenizer = null;

        public LightScanner(InputStream in) {
            reader = new BufferedReader(new InputStreamReader(in));
        }

        public String string() {
            if (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new UncheckedIOException(e);
                }
            }
            return tokenizer.nextToken();
        }

        public int ints() {
            return Integer.parseInt(string());
        }

        public int[] ints(int length) {
            return IntStream.range(0, length).map(x -> ints()).toArray();
        }

    }

    static class ModMath {
        private static final int DEFAULT_MOD = 1_000_000_007;
        private final long mod;

        public ModMath(long mod, boolean unsafe) {
        /*if (!unsafe && !IntMath.isPrime(mod)) {
            throw new RuntimeException("This class is designed for primes!");
        }*/
            this.mod = mod;
        }

        public ModMath(long mod) {
            this(mod, false);
        }

        public ModMath() {
            this(DEFAULT_MOD, true);
        }

        public long inv(long x) {
            return pow(x, mod - 2);
            //return mod(LongEuclidSolver.solve(x, mod).x);
        }

        public long pow(long x, long y) {
            y %= (mod - 1);
            if (y < 0) {
                return pow(inv(x), -y);
            } else if (y == 0) {
                return 1;
            } else if (y % 2 == 0) {
                long z = pow(x, y / 2);
                return (z * z) % mod;
            } else {
                return (x % mod) * pow(x, y - 1) % mod;
            }
        }

    }

    static class HeapSort {
        private HeapSort() {
        }

        private static void heapfy(int[] a, int low, int high, int i, int val) {
            int child = 2 * i - low + 1;
            while (child < high) {
                if (child + 1 < high && a[child] < a[child + 1]) {
                    child++;
                }
                if (val >= a[child]) {
                    break;
                }
                a[i] = a[child];
                i = child;
                child = 2 * i - low + 1;
            }
            a[i] = val;
        }

        static void sort(int[] a, int low, int high) {
            for (int p = (high + low) / 2 - 1; p >= low; p--) {
                heapfy(a, low, high, p, a[p]);
            }
            while (high > low) {
                high--;
                int pval = a[high];
                a[high] = a[low];
                heapfy(a, low, high, low, pval);
            }
        }

    }

    static class QuickSort {
        private QuickSort() {
        }

        private static void med(int[] a, int low, int x, int y, int z) {
            if (a[z] < a[x]) {
                ArrayUtil.swap(a, low, x);
            } else if (a[y] < a[z]) {
                ArrayUtil.swap(a, low, y);
            } else {
                ArrayUtil.swap(a, low, z);
            }
        }

        static int step(int[] a, int low, int high) {
            int x = low + 1, y = low + (high - low) / 2, z = high - 1;
            if (a[x] < a[y]) {
                med(a, low, x, y, z);
            } else {
                med(a, low, y, x, z);
            }

            int lb = low + 1, ub = high;
            while (true) {
                while (a[lb] < a[low]) {
                    lb++;
                }
                ub--;
                while (a[low] < a[ub]) {
                    ub--;
                }
                if (lb >= ub) {
                    return lb;
                }
                ArrayUtil.swap(a, lb, ub);
                lb++;
            }
        }

    }

    static final class ArrayUtil {
        private ArrayUtil() {
        }

        public static void swap(int[] a, int x, int y) {
            int t = a[x];
            a[x] = a[y];
            a[y] = t;
        }

    }
}