#include <bits/stdc++.h>
using namespace std;
const int MAXN = 2010;
int n, m, k;
char a[MAXN][MAXN];
int pref[MAXN][MAXN];
int getSumLine(int i, int j) {
  return pref[i][j + k - 1] - pref[i][j - 1] - pref[i - 1][j + k - 1] +
         pref[i - 1][j - 1];
}
int getSumRow(int i, int j) {
  return pref[i + k - 1][j] - pref[i - 1][j] - pref[i + k - 1][j - 1] +
         pref[i - 1][j - 1];
}
int main() {
  scanf("%d%d%d\n", &n, &m, &k);
  for (int i = 1; i <= n; i++) {
    scanf("%s", a[i] + 1);
  }
  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= m; j++) {
      if (a[i][j] == '*') {
        pref[i][j]++;
      }
      pref[i][j] += pref[i - 1][j];
      pref[i][j] += pref[i][j - 1];
      pref[i][j] -= pref[i - 1][j - 1];
    }
  }
  int ans = 0;
  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= m; j++) {
      if (i + k - 1 <= n) {
        if (getSumRow(i, j) == 0) ans++;
      }
      if (j + k - 1 <= m && k != 1) {
        if (getSumLine(i, j) == 0) ans++;
      }
    }
  }
  cout << ans;
  return 0;
}
