#include <iostream>
#include <algorithm>
#include <iomanip>
#include <vector>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <tuple>
#include <cmath>
#include <numeric>
#include <functional>
#include <cassert>
#include <atcoder/modint>

#define debug_value(x) cerr << "line" << __LINE__ << ":<" << __func__ << ">:" << #x << "=" << x << endl;
#define debug(x) cerr << "line" << __LINE__ << ":<" << __func__ << ">:" << x << endl;

template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }

using namespace std;
typedef long long ll;

template<typename T>
vector<vector<T>> vec2d(int n, int m, T v){
    return vector<vector<T>>(n, vector<T>(m, v));
}

template<typename T>
vector<vector<vector<T>>> vec3d(int n, int m, int k, T v){
    return vector<vector<vector<T>>>(n, vector<vector<T>>(m, vector<T>(k, v)));
}

template<typename T>
void print_vector(vector<T> v, char delimiter=' '){
    if(v.empty()) {
        cout << endl;
        return;
    }
    for(int i = 0; i+1 < v.size(); i++) cout << v[i] << delimiter;
    cout << v.back() << endl;
}

using mint = atcoder::modint998244353;

ostream& operator<<(ostream& os, const mint& m){
    os << m.val();
    return os;
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout << setprecision(10) << fixed;
    int h, w, k; cin >> h >> w >> k;
    vector<string> s(h);
    for(int i = 0; i < h; i++) cin >> s[i];
    auto hor = vec2d(h*2+5, w*2+5, mint(0));
    auto stop = vec2d(h*2+5, w*2+5, mint(0));
    vector<mint> cumsum(2*w+5);
    hor[0][0] = 1;
    hor[0][k+1] -= 1;
    stop[1][k] -= 1;
    for(int i = 0; i < h; i++){
        for(int j = 0; j < 2*w; j++){
            if(i > 0) stop[i][j] += stop[i-1][j+1];
            if(j > 0) hor[i][j] += hor[i][j-1];
            cumsum[j] += hor[i][j]+stop[i][j];
            mint dp = cumsum[j];
            if(i == 0 && j == 0) continue;
            if(j < w && s[i][j] == '.'){
                hor[i][j] += dp;
                if(j+k+1 < 2*w) hor[i][j+k+1] -= dp;
                cumsum[j] += dp;
                // cumsum[j+k+1] -= dp[i][j];
                if(j+k < 2*w)  stop[i+1][j+k] -= dp;
                if(j > 0 && i+k+2 < 2*h) stop[i+k+2][j-1] += dp;
            }
            if(i == h-1 && j == w-1){
                cout << dp << endl;
                return 0;
            }
        }
    }
}