MAX = 1000000
fac = [0]*(MAX+1)
inv = [0]*(MAX+1)
finv = [0]*(MAX+1)
mod = 998244353
fac[0] = fac[1] = finv[0] = finv[1] = inv[1] = 1
for i in range(2,MAX+1):
    fac[i] = fac[i-1]*i%mod
    inv[i] = mod-inv[mod%i]*(mod//i)%mod
    finv[i] = finv[i-1]*inv[i]%mod
def binom(n,r):
    if r<0 or n<0 or n<r:
        return 0
    return fac[n]*finv[r]%mod*finv[n-r]%mod

N,Q = map(int,input().split())
mem = [0]*(N+1)
for i in range(Q):
    L,R = map(int,input().split())
    mem[L-1] ^= (1<<i)
    mem[R] ^= (1<<i)
now = 0
cnt = dict()
for i in range(N):
    now ^= mem[i]
    if now in cnt:
        cnt[now] += 1
    else:
        cnt[now] = 1
ans = fac[N//2]*fac[N-N//2]%mod
for el in cnt:
    val = cnt[el]
    if val % 2:
        if el:
            ans = 0
        val += 1
    ans *= fac[val]*finv[val//2]%mod*finv[val//2+1]%mod
    ans %= mod
print(ans)