#include <bits/stdc++.h>
using namespace std;
int a[555][555], sum[555][555], b[555][555], n, m, kk;
char st[555];
int fsum(int i1, int j1, int i2, int j2) {
  ++i1;
  ++j1;
  --i2;
  --j2;
  return sum[i2][j2] - sum[i1 - 1][j2] - sum[i2][j1 - 1] + sum[i1 - 1][j1 - 1];
}
int main() {
  cin >> n >> m >> kk;
  gets(st);
  for (int i = 1; i <= n; i++) {
    gets(st);
    for (int j = 1; j <= m; j++)
      if (st[j - 1] == '0')
        a[i][j] = 0;
      else
        a[i][j] = 1;
  }
  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= m; j++) {
      int val = a[i][j] * a[i - 1][j] * a[i + 1][j] * a[i][j - 1] * a[i][j + 1];
      if (val != 0) b[i][j] = 1;
    }
  }
  for (int i = 1; i <= n; i++)
    for (int j = 1; j <= m; j++)
      sum[i][j] = sum[i - 1][j] + sum[i][j - 1] - sum[i - 1][j - 1] + b[i][j];
  long long ans = 0;
  for (int i = 3; i <= n; i++)
    for (int j = 3; j <= m; j++) {
      bool fl = false;
      long long pp;
      for (int k = 1; k <= i; k++) {
        if (k + 1 == i) break;
        if (fsum(k, 1, i, j) < kk) break;
        if (fl == true) {
          while (true) {
            int val = fsum(k, pp, i, j);
            if (val >= kk) break;
            --pp;
          }
          ans += pp;
          continue;
        }
        pp = 1;
        while (true) {
          if (pp + 2 == j) break;
          int val = fsum(k, pp + 1, i, j);
          if (val < kk) break;
          ++pp;
        }
        fl = true;
        ans += pp;
      }
    }
  cout << ans;
  return 0;
}
