#include <bits/stdc++.h>
using namespace std;
template <class T>
inline T sqr(T x) {
  return x * x;
}
const int maxn = 1000;
int n, m, val;
char s[maxn][maxn];
int f[maxn][maxn];
int sum[maxn][maxn];
long long res;
int main() {
  for (int i = 0; i < int(maxn); i++)
    for (int j = 0; j < int(maxn); j++) {
      s[i][j] = 0;
      f[i][j] = 0;
      sum[i][j] = 0;
    }
  cin >> n >> m >> val;
  for (int i = int(1); i < int(n + 1); i++)
    for (int j = int(1); j < int(m + 1); j++) cin >> s[i][j];
  for (int i = int(1); i < int(n + 1); i++)
    for (int j = int(1); j < int(m + 1); j++) {
      if (s[i][j] == '1' && s[i - 1][j] == '1' && s[i + 1][j] == '1' &&
          s[i][j - 1] == '1' && s[i][j + 1] == '1')
        f[i + 1][j + 1] = 1;
    }
  for (int i = int(1); i < int(n + 1); i++)
    for (int j = int(1); j < int(m + 1); j++) {
      sum[i][j] = (sum[i - 1][j] + sum[i][j - 1] - sum[i - 1][j - 1]) + f[i][j];
    }
  for (int i = int(1); i < int(n); i++)
    for (int j = int(1); j < int(m); j++) {
      for (int k = int(1); k < int(m - j + 2); k++) {
        int l = i + 1, r = n + 1, cur;
        while (l < r - 1) {
          cur = (l + r) >> 1;
          if (sum[cur][j + k - 1] - sum[cur][j + 1] - sum[i + 1][j + k - 1] +
                  sum[i + 1][j + 1] <
              val)
            l = cur;
          else
            r = cur;
        }
        res += n - l;
      }
    }
  cout << res << endl;
}
