#include <bits/stdc++.h>
#pragma comment(linker, "/STACK:25600000")
using namespace std;
const double pi = acos(-1.0);
int start[512][512];
int a[512][512];
int sums[512][512];
int n, m, k;
int count(int x1, int dfjbwdkfasdfasdfasdfb, int x2,
          int sdfskjoowomvsknsadife) {
  return sums[x2][sdfskjoowomvsknsadife] - sums[x2][dfjbwdkfasdfasdfasdfb - 1] -
         sums[x1 - 1][sdfskjoowomvsknsadife] +
         sums[x1 - 1][dfjbwdkfasdfasdfasdfb - 1];
}
int bbsearch(int x, int dfjbwdkfasdfasdfasdfb, int sdfskjoowomvsknsadife) {
  int mx = count(x, dfjbwdkfasdfasdfasdfb, n, sdfskjoowomvsknsadife);
  if (mx < k) return n + 1;
  int l = x;
  int r = n;
  while (r - l > 5) {
    int med = (l + r) / 2;
    if (count(x, dfjbwdkfasdfasdfasdfb, med, sdfskjoowomvsknsadife) >= k)
      r = med;
    else
      l = med;
  }
  for (long long ii = l; ii <= r; ii++)
    if (count(x, dfjbwdkfasdfasdfasdfb, ii, sdfskjoowomvsknsadife) >= k) {
      return ii;
    }
}
int main() {
  cin >> n >> m >> k;
  for (long long i = 0; i < n; i++) {
    string s;
    cin >> s;
    for (long long j = 0; j < m; j++)
      s[j] == '1' ? start[i + 1][j + 1] = 1 : start[i + 1][j + 1] = 0;
  }
  for (long long i = 2; i <= n - 1; i++)
    for (long long j = 2; j <= m - 1; j++) {
      if (start[i][j] && start[i - 1][j] && start[i + 1][j] &&
          start[i][j - 1] && start[i][j + 1])
        a[i][j] = 1;
      else
        a[i][j] = false;
    }
  long long total = 0;
  for (long long i = 1; i <= n; i++)
    for (long long j = 1; j <= m; j++)
      sums[i][j] =
          a[i][j] + sums[i - 1][j] + sums[i][j - 1] - sums[i - 1][j - 1];
  for (long long x = 2; x <= n; x++)
    for (long long dfjbwdkfasdfasdfasdfb = 2; dfjbwdkfasdfasdfasdfb <= m - 1;
         dfjbwdkfasdfasdfasdfb++)
      for (long long sdfskjoowomvsknsadife = dfjbwdkfasdfasdfasdfb;
           sdfskjoowomvsknsadife <= m - 1; sdfskjoowomvsknsadife++) {
        int x2 = bbsearch(x, dfjbwdkfasdfasdfasdfb, sdfskjoowomvsknsadife);
        if (x2 < n) total += (n - x2);
      }
  cout << total << endl;
}
