#include <bits/stdc++.h>
using namespace std;
const int MAX = 2e3 + 5;
char a[MAX][MAX];
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0), cout.tie(0);
  int n, m, k;
  cin >> n >> m >> k;
  for (int i = (1); i <= (n); ++i)
    for (int j = (1); j <= (m); ++j) cin >> a[i][j];
  int ans = 0;
  for (int i = (1); i <= (n); ++i) {
    int cnt = 0;
    for (int j = (1); j <= (m); ++j) {
      if (a[i][j] == '.')
        ++cnt;
      else {
        if (cnt >= k) ans += cnt - k + 1;
        cnt = 0;
      }
    }
    if (cnt >= k) ans += cnt - k + 1;
  }
  if (k > 1) {
    for (int i = (1); i <= (m); ++i) {
      int cnt = 0;
      for (int j = (1); j <= (n); ++j) {
        if (a[j][i] == '.')
          ++cnt;
        else {
          if (cnt >= k) ans += cnt - k + 1;
          cnt = 0;
        }
      }
      if (cnt >= k) ans += cnt - k + 1;
    }
  }
  cout << ans << '\n';
  return 0;
}
