#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
using namespace std;
using std::cout;
using std::cin;
using std::endl;
using ll=long long;
using ld=long double;
ll ILL=2167167167167167167;
const int INF=2100000000;
const int mod=998244353;
#define rep(i,a,b) for (int i=a;i<b;i++)
#define all(p) p.begin(),p.end()
template<class T> using _pq = priority_queue<T, vector<T>, greater<T>>;
template<class T> ll LB(vector<T> &v,T a){return lower_bound(v.begin(),v.end(),a)-v.begin();}
template<class T> ll UB(vector<T> &v,T a){return upper_bound(v.begin(),v.end(),a)-v.begin();}
template<class T> bool chmin(T &a,const T &b){if(a>b){a=b;return 1;}else return 0;}
template<class T> bool chmax(T &a,const T &b){if(a<b){a=b;return 1;}else return 0;}
template<class T> void So(vector<T> &v) {sort(v.begin(),v.end());}
template<class T> void Sore(vector<T> &v) {sort(v.begin(),v.end(),[](T x,T y){return x>y;});}
void yneos(bool a){if(a) cout<<"Yes\n"; else cout<<"No\n";}
template<class T> void vec_out(vector<T> &p){for(int i=0;i<(int)(p.size());i++){if(i) cout<<" ";cout<<p[i];}cout<<"\n";}
template<class T> T vec_min(vector<T> &a){assert(!a.empty());T ans=a[0];for(auto &x:a) chmin(ans,x);return ans;}
template<class T> T vec_max(vector<T> &a){assert(!a.empty());T ans=a[0];for(auto &x:a) chmax(ans,x);return ans;}
template<class T> T vec_sum(vector<T> &a){assert(!a.empty());T ans=a[0]-a[0];for(auto &x:a) ans+=x;return ans;}


void solve();
// oddloop
int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	
	int t=1;
	//cin>>t;
	rep(i,0,t) solve();
}

void solve(){
	int H,W,K;
	cin>>H>>W>>K;
	vector<vector<char>> masu(H+1,vector<char>(1+W,'?'));
	rep(i,1,1+H) rep(j,1,1+W){
		cin>>masu[i][j];
	}
	if(H>W){
		vector<vector<char>> n_masu(W+1,vector<char>(H+1));
		rep(i,0,H+1) rep(j,0,W+1) n_masu[j][i]=masu[i][j];
		swap(n_masu,masu);
		swap(H,W);
	}
	vector<vector<ll>> p(H+1,vector<ll>(W+1));
	vector<vector<ll>> q(H+1,vector<ll>(W+1));
	p[1][1]=1;
	q[1][1]=1;
	rep(sum,3,H+W+1){
		ll tmp=0;
		for(int i=1;i<=H&&i<sum;i++){
			int j=sum-i;
			tmp=(tmp+p[i][min(j-1,W)]-p[i][max(0,j-K-1)])%mod;
			if(j>W) continue;
			p[i][j]=p[i][j-1];
			q[i][j]=q[i-1][j];
			if(masu[i][j]=='.'){
				p[i][j]=(p[i][j]+tmp)%mod;
				q[i][j]=(q[i][j]+tmp)%mod;
			}
			tmp=(tmp-q[i-1][j]+q[max(0,i-K-1)][j])%mod;
		}
	}
	cout<<(q[H][W]-q[H-1][W]+mod+mod)%mod<<"\n";
}