#from bisect import bisect_left as bl                #c++ lowerbound bl(array,element)
#from bisect import bisect_right as br               #c++ upperbound br(array,element)
#from __future__ import print_function, division    #while using python2
# from itertools import accumulate
# from collections import defaultdict, Counter

def modinv(n,p):
    return pow(n,p-2,p)

def main():
    #sys.stdin = open('input.txt', 'r')
    #sys.stdout = open('output.txt', 'w')

    mod = 998244353
    dp = [0] * (200005)
    suffix = [0] * (200005)
    segments = []

    n, k = [int(x) for x in input().split()]
    for i in range(k):
        segments.append([int(x) for x in input().split()])

    segments.sort()

    dp[n] = 1
    suffix[n] = 1
    not_possible = False
    for x in range(n-1, 0, -1):
        for l, r in segments:
            if x + l > n:
                # suffix[x] = suffix[x+1]
                break
            if x + r > n:
                r = n - x
            # dp[x] = dp[x] + max(0, (suffix[x+l] - suffix[x+r+1]))
            # dp[x] %= mod
            # if(suffix[x+l] - suffix[x+r+1] > 0):
            dp[x] = (dp[x] + (suffix[x+l] - suffix[x+r+1])) % mod
            suffix[x] = (dp[x] + suffix[x+1]) % mod

            # print(x)
            # print(l, r)
            # print(dp[:n+1])
            # print(suffix[:n+1])
            # print()
        if suffix[x] == 0:
            suffix[x] = suffix[x+1]

    print(dp[1])

#------------------ Python 2 and 3 footer by Pajenegod and c1729-----------------------------------------
py2 = round(0.5)
if py2:
    from future_builtins import ascii, filter, hex, map, oct, zip
    range = xrange

import os, sys
from io import IOBase, BytesIO

BUFSIZE = 8192
class FastIO(BytesIO):
    newlines = 0
    def __init__(self, file):
        self._file = file
        self._fd = file.fileno()
        self.writable = "x" in file.mode or "w" in file.mode
        self.write = super(FastIO, self).write if self.writable else None

    def _fill(self):
        s = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
        self.seek((self.tell(), self.seek(0,2), super(FastIO, self).write(s))[0])
        return s
    def read(self):
        while self._fill(): pass
        return super(FastIO,self).read()

    def readline(self):
        while self.newlines == 0:
            s = self._fill(); self.newlines = s.count(b"\n") + (not s)
        self.newlines -= 1
        return super(FastIO, self).readline()

    def flush(self):
        if self.writable:
            os.write(self._fd, self.getvalue())
            self.truncate(0), self.seek(0)

class IOWrapper(IOBase):
    def __init__(self, file):
        self.buffer = FastIO(file)
        self.flush = self.buffer.flush
        self.writable = self.buffer.writable
        if py2:
            self.write = self.buffer.write
            self.read = self.buffer.read
            self.readline = self.buffer.readline
        else:
            self.write = lambda s:self.buffer.write(s.encode('ascii'))
            self.read = lambda:self.buffer.read().decode('ascii')
            self.readline = lambda:self.buffer.readline().decode('ascii')

sys.stdin, sys.stdout = IOWrapper(sys.stdin), IOWrapper(sys.stdout)
input = lambda: sys.stdin.readline().rstrip('\r\n')

if __name__ == '__main__':
   main()


Measured memory_bytes: 71724