#include <bits/stdc++.h>
using namespace std;
const int inf = 1 << 28;
const double INF = 1e12, EPS = 1e-9;
int n, m, k;
bool star[600][600];
int sum[600][600];
char in[600][600];
void run() {
  cin >> n >> m >> k;
  for (int i = 0; i < n; i++) cin >> in[i];
  for (int i = 0; i < n; i++)
    for (int j = 0; j < m; j++) {
      if (in[i][j] == '1' && in[i + 1][j] == '1' && in[i + 2][j] == '1' && j &&
          in[i + 1][j - 1] == '1' && in[i + 1][j + 1] == '1')
        star[i][j] = 1;
    }
  long long ans = 0;
  for (int i = 0; i < n; i++)
    for (int j = 0; j < m; j++)
      sum[i + 1][j + 1] =
          star[i][j] + sum[i][j + 1] + sum[i + 1][j] - sum[i][j];
  for (int a = 0; a < n; a++)
    for (int b = a + 3; b <= n; b++) {
      int l = 0, r = 2, cnt = 0;
      for (; l < m; l++) {
        while (r <= m && cnt < k) {
          r++;
          cnt += sum[b - 2][r - 1] - sum[a][r - 1] -
                 (sum[b - 2][r - 2] - sum[a][r - 2]);
        }
        if (cnt < k || r > m) break;
        ans += m - r + 1;
        cnt -= sum[b - 2][l + 2] - sum[a][l + 2] -
               (sum[b - 2][l + 1] - sum[a][l + 1]);
      }
    }
  cout << ans << endl;
}
int main() { run(); }
