#include <bits/stdc++.h>
using namespace std;
template <class T>
inline void rread(T& num) {
  num = 0;
  T f = 1;
  char ch = getchar();
  while (ch < '0' || ch > '9') {
    if (ch == '-') f = -1;
    ch = getchar();
  }
  while (ch >= '0' && ch <= '9') num = num * 10 + ch - '0', ch = getchar();
  num *= f;
}
const long long inf = 1e18;
const int maxn = 5e5 + 10, mod = 1e9 + 7;
const int mod1 = 1e8 + 7, mod2 = 41;
const double pi = acos(-1);
long long gcd(long long a, long long b) { return (a ? gcd(b % a, a) : b); }
void exgcd(long long a, long long b, long long& d, long long& x, long long& y) {
  if (!b) {
    d = a;
    x = 1;
    y = 0;
  } else {
    exgcd(b, a % b, d, y, x);
    y -= x * (a / b);
  }
}
complex<double> power(complex<double> a, int n) {
  complex<double> p = 1;
  while (n > 0) {
    if (n % 2) {
      p = p * a;
    }
    n >>= 1;
    a *= a;
  }
  return p;
}
unsigned long long power(unsigned long long a, unsigned long long n) {
  unsigned long long p = 1;
  while (n > 0) {
    if (n % 2) {
      p = p * a;
    }
    n >>= 1;
    a *= a;
  }
  return p;
}
long long power(long long a, long long n) {
  long long p = 1;
  while (n > 0) {
    if (n % 2) {
      p = p * a;
    }
    n >>= 1;
    a *= a;
  }
  return p;
}
long long power(long long a, long long n, long long mod) {
  long long p = 1;
  while (n > 0) {
    if (n % 2) {
      p = p * a;
      p %= mod;
    }
    n >>= 1;
    a *= a;
    a %= mod;
  }
  return p % mod;
}
int n, m, k;
char s[2300][2300];
int main() {
  int kase = 1;
  while (cin >> n >> m >> k) {
    for (int i = 0; i < n; i++) scanf("%s", s[i]);
    int ans = 0;
    for (int i = 0; i < n; i++) {
      int cc = 0;
      for (int j = 0; j < m; j++) {
        if (s[i][j] == '.')
          cc++;
        else {
          ans += max(0, cc - k + 1);
          cc = 0;
        }
      }
      ans += max(0, cc - k + 1);
    }
    if (k == 1) {
      cout << ans << endl;
      continue;
    }
    for (int i = 0; i < m; i++) {
      int cc = 0;
      for (int j = 0; j < n; j++) {
        if (s[j][i] == '.')
          cc++;
        else {
          ans += max(0, cc - k + 1);
          cc = 0;
        }
      }
      ans += max(0, cc - k + 1);
    }
    cout << ans << endl;
  }
  return 0;
}
