
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
import java.util.Random;
import java.util.StringTokenizer;

public final class Main {

    private static final int MOD = 998244353;

    public static void main(String[] args) {
        final FastScanner fs = new FastScanner();
        final int n = fs.nextInt();
        final int k = fs.nextInt();
        final List<Integer> segments = new ArrayList<>();
        for (int i = 0; i < k; i++) {
            final int l = fs.nextInt();
            final int r = fs.nextInt();
            for (int point = l; point <= r; point++) {
                segments.add(point);
            }
        }
        System.out.println(dfs(n, 1, segments, new Long[n]) % MOD);
    }

    private static long dfs(int n, int pos,  List<Integer> jumps, Long[] dp) {
        if (pos >= n) {
            return pos == n ? 1 : 0;
        }
        if (dp[pos] != null) {
            return dp[pos];
        }
        long res = 0;
        for (int j : jumps) {
            res = (res + dfs(n, pos + j, jumps, dp)) % MOD;
        }
        return dp[pos] = res;
    }

    static final class Utils {
        public static void shuffleSort(int[] arr) {
            shuffle(arr);
            Arrays.sort(arr);
        }

        public static void shuffleSort(long[] arr) {
            shuffle(arr);
            Arrays.sort(arr);
        }

        public static void shuffle(int[] arr) {
            final Random r = new Random();

            for (int i = 0; i <= arr.length - 2; i++) {
                final int j = i + r.nextInt(arr.length - i);
                swap(arr, i, j);
            }
        }

        public static void shuffle(long[] arr) {
            final Random r = new Random();

            for (int i = 0; i <= arr.length - 2; i++) {
                final int j = i + r.nextInt(arr.length - i);
                swap(arr, i, j);
            }
        }

        public static void swap(int[] arr, int i, int j) {
            final int t = arr[i];
            arr[i] = arr[j];
            arr[j] = t;
        }

        public static void swap(long[] arr, int i, int j) {
            final long t = arr[i];
            arr[i] = arr[j];
            arr[j] = t;
        }

        private Utils() {}
    }

    static class FastScanner {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st = new StringTokenizer("");

        private String next() {
            while (!st.hasMoreTokens()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    //noinspection CallToPrintStackTrace
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

        int nextInt() {
            return Integer.parseInt(next());
        }

        long nextLong() {
            return Long.parseLong(next());
        }

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

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