import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.Reader;
import java.io.InputStreamReader;
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;
        MyInput in = new MyInput(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskC solver = new TaskC();
        solver.solve(1, in, out);
        out.close();
    }

    static class TaskC {
        static final int mod = 998244353;

        public void solve(int testNumber, MyInput in, PrintWriter out) {
            int n = in.nextInt();
            long[] w = new long[(int) 1e6 + 1];
            int[] inv = modInverse(w.length, mod);
            for (int i = 1; i < w.length; i++) {
                w[i] += inv[i];
                if (w[i] >= mod) w[i] -= mod;
                for (int j = 2 * i; j < w.length; j += i) {
                    w[j] -= w[i];
                    if (w[j] < 0) w[j] += mod;
                }
            }

            long[] sum1 = new long[w.length + 1];
            long[] sum2 = new long[w.length + 1];
            for (int a : in.nextIntArray(n)) {
                sum1[a] += a;
                sum2[a] += a * (long) a % mod;
            }

            long ans = 0;
            for (int i = 1; i < w.length; i++) {
                long s1 = 0;
                long s2 = 0;
                for (int j = i; j < w.length; j += i) {
                    s1 += sum1[j];
                    s2 += sum2[j];
                }
                s1 %= mod;
                s2 %= mod;
                long s = ((s1 * s1 - s2) % mod * inv[2] % mod + mod) % mod;
                ans += w[i] * s % mod;
            }
            out.println(ans % mod);
        }

        static int[] modInverse(int n, int m) {
            final int[] ret = new int[n + 1];
            ret[1] = 1;
            for (int i = 2; i <= n; i++) {
                ret[i] = (int) (ret[m % i] * (long) (m - m / i) % m);
            }
            return ret;
        }

    }

    static class MyInput {
        private final BufferedReader in;
        private static int pos;
        private static int readLen;
        private static final char[] buffer = new char[1024 * 8];
        private static char[] str = new char[500 * 8 * 2];
        private static boolean[] isDigit = new boolean[256];
        private static boolean[] isSpace = new boolean[256];
        private static boolean[] isLineSep = new boolean[256];

        static {
            for (int i = 0; i < 10; i++) {
                isDigit['0' + i] = true;
            }
            isDigit['-'] = true;
            isSpace[' '] = isSpace['\r'] = isSpace['\n'] = isSpace['\t'] = true;
            isLineSep['\r'] = isLineSep['\n'] = true;
        }

        public MyInput(InputStream is) {
            in = new BufferedReader(new InputStreamReader(is));
        }

        public int read() {
            if (pos >= readLen) {
                pos = 0;
                try {
                    readLen = in.read(buffer);
                } catch (IOException e) {
                    throw new RuntimeException();
                }
                if (readLen <= 0) {
                    throw new MyInput.EndOfFileRuntimeException();
                }
            }
            return buffer[pos++];
        }

        public int nextInt() {
            int len = 0;
            str[len++] = nextChar();
            len = reads(len, isSpace);
            int i = 0;
            int ret = 0;
            if (str[0] == '-') {
                i = 1;
            }
            for (; i < len; i++) ret = ret * 10 + str[i] - '0';
            if (str[0] == '-') {
                ret = -ret;
            }
            return ret;
        }

        public char nextChar() {
            while (true) {
                final int c = read();
                if (!isSpace[c]) {
                    return (char) c;
                }
            }
        }

        int reads(int len, boolean[] accept) {
            try {
                while (true) {
                    final int c = read();
                    if (accept[c]) {
                        break;
                    }
                    if (str.length == len) {
                        char[] rep = new char[str.length * 3 / 2];
                        System.arraycopy(str, 0, rep, 0, str.length);
                        str = rep;
                    }
                    str[len++] = (char) c;
                }
            } catch (MyInput.EndOfFileRuntimeException e) {
            }
            return len;
        }

        public int[] nextIntArray(final int n) {
            final int[] res = new int[n];
            for (int i = 0; i < n; i++) {
                res[i] = nextInt();
            }
            return res;
        }

        static class EndOfFileRuntimeException extends RuntimeException {
        }

    }
}



Measured memory_bytes: 53128