#include #include #include #include #include #include #include #include #include #include #include #include #include #include #define debug_value(x) cerr << "line" << __LINE__ << ":<" << __func__ << ">:" << #x << "=" << x << endl; #define debug(x) cerr << "line" << __LINE__ << ":<" << __func__ << ">:" << x << endl; template inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; } template inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; } using namespace std; typedef long long ll; template vector> vec2d(int n, int m, T v){ return vector>(n, vector(m, v)); } template vector>> vec3d(int n, int m, int k, T v){ return vector>>(n, vector>(m, vector(k, v))); } template void print_vector(vector 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 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 cumsum(2*w+k+5); hor[0][0] = 1; if(k <= 2*w){ 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; } } } }