#include<bits/stdc++.h>
namespace {
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-function"
#include<atcoder/all>
#pragma GCC diagnostic pop
using namespace std;
using namespace atcoder;
#define rep(i,n) for(int i = 0; i < (int)(n); i++)
#define rrep(i,n) for(int i = (int)(n) - 1; i >= 0; i--)
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
template<class T> bool chmax(T& a, const T& b) { if (a < b) { a = b; return true; } else return false; }
template<class T> bool chmin(T& a, const T& b) { if (b < a) { a = b; return true; } else return false; }
using ll = long long;
using P = pair<int,int>;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<ll>;
using VVL = vector<VL>;
using mint = modint998244353;

} int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int h, w, k;
  cin >> h >> w >> k;
  k++;
  vector<string> S(h);
  rep(i, h) cin >> S[i];
  vector dp(h, vector<mint>(w)), d = dp;
  dp[0][0] = d[0][0] = 1;
  for (int s = 1; s <= h - 1 + w - 1; s++) {
    int s1 = s - k;
    int s2 = s1 - 1;
    int l1 = s1 - min(w - 1, s1), r1 = l1, r1_last = min(h - 1, s1) + 1;
    int l2 = s2 - min(w - 1, s2), r2 = l2, r2_last = min(h - 1, s2) + 1;
    mint v;
    for (int p = s - min(w - 1, s), p_last = min(h - 1, s), q = s - p; p <= p_last; p++, q--) {
      while (r1 < r1_last && r1 <= p) v -= dp[r1][s1 - r1], r1++;
      while (l1 < r1 && s1 - l1 > q) v += dp[l1][s1 - l1], l1++;
      while (r2 < r2_last && r2 <= p) v += dp[r2][s2 - r2], r2++;
      while (l2 < r2 && s2 - r2 > q) v -= dp[l2][s2 - l2], l2++;
      mint w = v;
      if (p) w += d[p-1][q];
      if (q) w += d[p][q-1];
      if (p && q) w -= d[p-1][q-1];
      d[p][q] += w;
      if (S[p][q] != '#') {
        dp[p][q] = w;
        d[p][q] += w;
      }
    }
  }
  cout << dp[h - 1][w - 1].val() << '\n';
}