#include<iostream>
#include<atcoder/modint>
#include<atcoder/lazysegtree>
using namespace std;
using mint=atcoder::modint998244353;
using dat=pair<mint,mint>;//(val, len)
dat op(dat a,dat b){return make_pair(a.first+b.first,a.second+b.second);}
dat e(){return make_pair(mint::raw(0),mint::raw(0));}
using F=pair<mint,mint>;//(mul, add)
dat mp(F f,dat x){return make_pair(x.first*f.first+x.second*f.second,x.second);}
F cmp(F f,F g){return make_pair(g.first*f.first,g.second*f.first+f.second);}
F id(){return make_pair(mint::raw(1),mint::raw(0));}
int N,M;
int A[2<<17],sign[2<<17];
long S[2<<17];
main()
{
	cin>>N>>M;
	for(int i=0;i<N;i++)
	{
		cin>>A[i];
		sign[i]=(N-i)%2==1?-1:1;
		S[i+1]=S[i]+A[i]*sign[i];
	}
	if(S[N]%M!=0)
	{
		cout<<-1<<endl;
		return 0;
	}
	atcoder::lazy_segtree<dat,op,e,F,mp,cmp,id>seg(vector<dat>(M,make_pair(mint::raw(0),mint::raw(1))));
	seg.set(0,make_pair(mint::raw(1),mint::raw(1)));
	int off=0;
	mint ans=1;
	for(int i=N-1;i>=0;i--)
	{
		if(sign[i]==1)
		{
			//0<=a<A[i], seg[S[i]+a-off]
			//S[i]-off<=*<S[i]+A[i]-off
			int L=((S[i]-off)%M+M)%M;
			int R=((S[i]+A[i]-off)%M+M)%M;
			if(L<=R)ans+=seg.prod(L,R).first;
			else ans+=seg.prod(L,M).first+seg.prod(0,R).first;
		}
		else
		{
			//0<=a<A[i], seg[S[i]-a-off]
			//S[i]-A[i]-off<*<=S[i]-off
			//S[i]-A[i]-off+1<=*<S[i]-off+1
			int L=((S[i]-A[i]-off+1)%M+M)%M;
			int R=((S[i]-off+1)%M+M)%M;
			if(L<=R)ans+=seg.prod(L,R).first;
			else ans+=seg.prod(L,M).first+seg.prod(0,R).first;
		}
		mint s=seg.all_prod().first;
		seg.apply(0,M,make_pair(mint(-1),s));
		if(sign[i]==-1)off=(off-1+M)%M;
		else off=(off+1)%M;
	}
	cout<<ans.val()<<endl;
}