#include<iostream>
#include<cstdio>
#include<vector>
#include<algorithm>
#define N 200000
#define K 19
#define M 524288
#define g 3
#define mod 998244353
using namespace std;
const int inv2=(mod+1)>>1;
int read()
{
	char c=0;
	int sum=0,f=1;
	while (c!='-'&&(c<'0'||c>'9')) c=getchar();
	if (c=='-') c=getchar(),f=-1;
	while ('0'<=c&&c<='9') sum=sum*10+c-'0',c=getchar();
	return sum*f;
}
int fast_pow(int a,int b)
{
	int res=1,mul=a;
	while (b)
	{
		if (b&1) res=1ll*res*mul%mod;
		mul=1ll*mul*mul%mod,b>>=1;
	}
	return res;
}
int MD(int x)
{
	return x>=mod?x-mod:x;
}
int MD2(int x)
{
	return x<0?x+mod:x;
}
void Adder(int &x,int d)
{
	x=x+d>=mod?x+d-mod:x+d;
	return;
}
void Adder2(int &x,int d)
{
	x=x+d<0?x+d+mod:x+d;
	return;
}
int n,m,dst,length,wres=1,ans,cnt,num[M+1],rev[M+1],inv[M+1],tA[N+1],tB[N+1],A[M+1],B[M+1],C[M+1],D[M+1],s[N+1],s2[N+1],l[N+1],r[N+1],scnt[N+1],scnt2[N+1],delta[N+1],delta2[N+1],dp[N+1],dp2[N+1],dp3[N+1],dp4[N+1],wn[K+1][M+1],wn2[K+1][M+1];
void NTT(int limit,int *s,int type)
{
	int s1,s2;
	for (int i=1;i<limit;++i) rev[i]=(rev[i>>1]>>1)|((i&1)?limit>>1:0);
	for (int i=0;i<limit;++i)
		if (rev[i]>i)
			swap(s[i],s[rev[i]]);
	if (type==1)
	{
		for (int i=2;i<=limit;i<<=1)
			for (int j=0;j+i-1<limit;j+=i)
				for (int k=j;k<(j|(i>>1));++k)
					s1=s[k],s2=1ll*s[k|(i>>1)]*wn[num[i]][k-j]%mod,s[k]=MD(s1+s2),s[k+(i>>1)]=MD2(s1-s2);
	}
	else
	{
		for (int i=2;i<=limit;i<<=1)
			for (int j=0;j+i-1<limit;j+=i)
				for (int k=j;k<(j|(i>>1));++k)
					s1=s[k],s2=1ll*s[k|(i>>1)]*wn2[num[i]][k-j]%mod,s[k]=MD(s1+s2),s[k+(i>>1)]=MD2(s1-s2);
		s1=fast_pow(limit,mod-2);
		for (int i=0;i<=limit;++i) s[i]=1ll*s[i]*s1%mod;
	}
	return;
}
vector<int>operator * (vector<int>a,vector<int>b)
{
	if (a.empty()) return a;
	if (b.empty()) return b;
	vector<int>c(a.size()+b.size()-1);
	if (min(a.size(),b.size())<=50)
	{
		for (int i=0;i<a.size();++i)
			for (int j=0;j<b.size();++j)
				Adder(c[i+j],1ll*a[i]*b[j]%mod);
		return c;
	}
	int limit=1;
	while (limit<=a.size()+b.size()) limit<<=1;
	for (int i=0;i<=limit;++i) A[i]=B[i]=0;
	for (int i=0;i<a.size();++i) A[i]=a[i];
	for (int i=0;i<b.size();++i) B[i]=b[i];
	NTT(limit,A,1),NTT(limit,B,1);
	for (int i=0;i<=limit;++i) A[i]=1ll*A[i]*B[i]%mod;
	NTT(limit,A,-1);
	for (int i=0;i<c.size();++i) c[i]=A[i];
	return c;
}
vector<int>get_pow(vector<int>p,int b)
{
	vector<int>tres={1};
	vector<int>mul=p;
	while (b)
	{
		if (b&1) tres=tres*mul;
		mul=mul*mul,b>>=1;
	}
	return tres;
}
vector<int>operator / (vector<int>a,vector<int>b)
{
	vector<int>c(a.size()-b.size()+1);
	if (min(b.size(),c.size())<=50)
	{
		for (int i=0;i<c.size();++i)
			for (int j=0;j<b.size();++j)
				Adder(c[i],1ll*b[j]*a[i+j]%mod);
		return c;
	}
	int limit=1;
	while (limit<=a.size()) limit<<=1;
	for (int i=0;i<=limit;++i) A[i]=B[i]=0;
	for (int i=0;i<a.size();++i) A[i]=a[i];
	for (int i=0;i<b.size();++i) B[b.size()-i]=b[i];
	NTT(limit,A,1),NTT(limit,B,1);
	for (int i=0;i<=limit;++i) A[i]=1ll*A[i]*B[i]%mod;
	NTT(limit,A,-1);
	for (int i=0;i<c.size();++i) c[i]=A[b.size()+i];
	return c;
}
vector<int>get_rev(int sz,vector<int>a)
{
	a.resize(sz+1),reverse(a.begin(),a.end());
	return a;
}
void calc_inv(int len,int *s1,int *s2)
{
	if (len==1)
	{
		s2[0]=fast_pow(s1[0],mod-2);
		return;
	}
	int limit=1;
	while (limit<=(len<<1)) limit<<=1;
	calc_inv((len+1)>>1,s1,s2);
	int s3[limit+1];
	for (int i=0;i<=limit;++i) s2[i]=(i<((len+1)>>1))?s2[i]:0,s3[i]=(i<len)?s1[i]:0;
	NTT(limit,s2,1),NTT(limit,s3,1);
	for (int i=0;i<=limit;++i) s2[i]=MD2(2ll*s2[i]%mod-1ll*s2[i]*s2[i]%mod*s3[i]%mod);
	NTT(limit,s2,-1);
	for (int i=0;i<=limit;++i) s2[i]=(i<len)?s2[i]:0;
	return;
}
vector<int>get_inv(int len,vector<int>p)
{
	vector<int>v(len);
	for (int i=0;i<min(len,(int)(p.size()));++i) C[i]=p[i];
	calc_inv(len,C,D);
	for (int i=0;i<len;++i) v[i]=D[i];
	return v;
}
void calc_ln(int len,int *s1,int *s2)
{
	int limit=1;
	while (limit<=(len<<1)) limit<<=1;
	calc_inv(len,s1,s2);
	int s3[limit+1];
	for (int i=0;i<=limit;++i) s3[i]=(i<len)?1ll*s1[i+1]*(i+1)%mod:0;
	NTT(limit,s2,1),NTT(limit,s3,1);
	for (int i=0;i<=limit;++i) s2[i]=1ll*s2[i]*s3[i]%mod;
	NTT(limit,s2,-1);
	for (int i=0;i<=limit;++i) s2[i]=(i<len)?s2[i]:0;
	for (int i=len-1;i>=1;--i) s2[i]=1ll*s2[i-1]*inv[i]%mod;
	s2[0]=0;
	return;
}
vector<int>get_ln(int len,vector<int>p)
{
	vector<int>v(len);
	for (int i=0;i<min(len,(int)(p.size()));++i) C[i]=p[i];
	calc_ln(len,C,D);
	for (int i=0;i<len;++i) v[i]=D[i];
	return v;
}
void calc_exp(int len,int *s1,int *s2)
{
	if (len==1)
	{
		s2[0]=1;
		return;
	}
	int limit=1;
	while (limit<=(len<<1)) limit<<=1;
	int s3[limit+1],s4[limit+1],s5[limit+1];
	for (int i=0;i<=limit;++i) s3[i]=0;
	calc_exp((len+1)>>1,s1,s2),calc_ln(len,s2,s3);
	for (int i=0;i<=limit;++i) s4[i]=i<len?s2[i]:0,s5[i]=(i<len)?MD2((!i)+s1[i]-s3[i]):0;
	NTT(limit,s4,1),NTT(limit,s5,1);
	for (int i=0;i<=limit;++i) s2[i]=1ll*s4[i]*s5[i]%mod;
	NTT(limit,s2,-1);
	for (int i=0;i<=limit;++i) s2[i]=i<len?s2[i]:0;
	return;
}
vector<int>get_exp(int len,vector<int>p)
{
	vector<int>v(len);
	for (int i=0;i<min(len,(int)(p.size()));++i) C[i]=p[i];
	calc_exp(len,C,D);
	for (int i=0;i<len;++i) v[i]=D[i];
	return v;
}
void reverse(int len,int *s)
{
	for (int i=0;i<(len>>1);++i) swap(s[i],s[len-1-i]);
	return;
}
void get_div(int len1,int len2,int *s1,int *s2,int *s3,int *s4)
{
	int limit=1;
	while (limit<=(len1<<1)) limit<<=1;
	int s5[limit+1],s6[limit+1];
	for (int i=0;i<=limit;++i) s3[i]=0,s5[i]=(i<len1)?s1[i]:0,s6[i]=(i<len2)?s2[i]:0;
	reverse(len1,s5),reverse(len2,s6),calc_inv(len1-len2+1,s6,s3);
	NTT(limit,s3,1),NTT(limit,s5,1);
	for (int i=0;i<=limit;++i) s3[i]=1ll*s3[i]*s5[i]%mod;
	NTT(limit,s3,-1);
	for (int i=0;i<=limit;++i) s3[i]=(i<len1-len2+1)?s3[i]:0;
	reverse(len1-len2+1,s3),reverse(len2,s6);
	for (int i=0;i<=limit;++i) s4[i]=s3[i];
	NTT(limit,s4,1),NTT(limit,s6,1);
	for (int i=0;i<=limit;++i) s4[i]=1ll*s4[i]*s6[i]%mod;
	NTT(limit,s4,-1);
	for (int i=0;i<=limit;++i) s4[i]=(i<len2-1)?MD2(s1[i]-s4[i]):0;
	return;
}
vector<int>operator % (vector<int>a,vector<int>b)
{
	if (a.size()<b.size()) return a;
	vector<int>c(b.size()-1);
	for (int i=0;i<a.size();++i) A[i]=a[i];
	for (int i=0;i<b.size();++i) B[i]=b[i];
	get_div(a.size(),b.size(),A,B,C,D);
	for (int i=0;i<c.size();++i) c[i]=D[i];
	return c;
}
struct seg
{
	struct node
	{
		int l,r;
		vector<int>p;
		vector<int>v;
	};
	node tree[(N<<2)+1];
	void push_up(int k)
	{
		tree[k].p=tree[k<<1].p*tree[k<<1|1].p,tree[k].v=tree[k<<1].v*tree[k<<1|1].v;
		return;
	}
	void build(int k,int l,int r)
	{
		tree[k].l=l,tree[k].r=r;
		if (l==r)
		{
			tree[k].p=get_pow({l,1},scnt[l]),tree[k].v={MD2(-l),1};
			return;
		}
		int mid=(l+r)>>1;
		build(k<<1,l,mid),build(k<<1|1,mid+1,r),push_up(k);
		return;
	}
	void solve(int k,vector<int>st)
    {
		if (tree[k].l==tree[k].r)
		{
			delta2[tree[k].l]=st[0],delta[tree[k].l]=((st*tree[k].p)%tree[k].v)[0];
			return;
		}
		solve(k<<1,(st*tree[k<<1|1].p)%tree[k<<1].v),solve(k<<1|1,st%tree[k<<1|1].v);
		return;
	}
};
seg T;
int main()
{
	int rst;
	inv[1]=1;
	for (int i=2;i<=M;++i) inv[i]=MD2(-1ll*(mod/i)*inv[mod%i]%mod);
	for (int i=2,w;i<=M;i<<=1)
	{
		num[i]=++length,w=fast_pow(g,(mod-1)/i);
		for (int j=0,res=1;j<(i>>1);++j,res=1ll*res*w%mod) wn[num[i]][j]=res;
		w=fast_pow(g,(mod-1)/i*(i-1));
		for (int j=0,res=1;j<(i>>1);++j,res=1ll*res*w%mod) wn2[num[i]][j]=res;
	}
	n=read(),m=read(),dst=(((1ll*m*(m+1))>>1))%mod,tA[0]=tB[m+1]=1;
	for (int i=1;i<=m;++i) tA[i]=tB[i]=s[i]=s2[i]=1;
	for (int i=1;i<=n;++i)
	{
		l[i]=read(),r[i]=read();
		if (l[i]!=-1&&r[i]!=-1) s[l[i]]=2ll*s[l[i]]%mod,s[r[i]+1]=1ll*s[r[i]+1]*inv2%mod,s2[l[i]]=2ll*s2[l[i]]%mod,s2[r[i]]=1ll*s2[r[i]]*inv2%mod;
		else if (l[i]==-1&&r[i]!=-1) wres=1ll*wres*r[i]%mod,tA[r[i]]=1ll*tA[r[i]]*r[i]%mod,scnt[r[i]]++;
		else if (l[i]!=-1&&r[i]==-1) wres=1ll*wres*(m-l[i]+1)%mod,tB[l[i]]=1ll*tB[l[i]]*(m-l[i]+1)%mod,scnt2[m-l[i]+1]++;
		else wres=1ll*wres*dst%mod,cnt++;
	}
	for (int i=1;i<=m;++i) tA[i]=1ll*tA[i]*tA[i-1]%mod;
	for (int i=m;i>=1;--i) tB[i]=1ll*tB[i]*tB[i+1]%mod;
	for (int i=2;i<=m;++i) s[i]=1ll*s[i]*s[i-1]%mod,s2[i]=1ll*s2[i]*s2[i-1]%mod;
	T.build(1,1,m),T.solve(1,{1});
	for (int i=1;i<=m;++i) dp[i]=delta[i],dp2[i]=delta2[i],swap(scnt[i],scnt2[i]);
	T.build(1,1,m),T.solve(1,{1});
	for (int i=1;i<=m;++i) dp3[i]=delta[i],dp4[i]=delta2[i];
	for (int i=1;i<=m;++i)
	{
		rst=1ll*s[i]*tA[i-1]%mod*tB[i+1]%mod*fast_pow(MD(dst+1ll*i*(m-i+1)%mod),cnt)%mod*dp[i]%mod*dp3[m-i+1]%mod;
		Adder(ans,MD2(rst-wres));
	}
	for (int i=1;i<=m-1;++i)
	{
		rst=1ll*s2[i]*tA[i]%mod*tB[i+1]%mod*fast_pow(MD(dst+1ll*i*(m-i)%mod),cnt)%mod*dp2[i]%mod*dp4[m-i]%mod;
		Adder2(ans,-MD2(rst-wres));
	}
	printf("%d\n",ans);
	return 0;
}