#include <bits/stdc++.h>
using namespace std;
const int maxn = 5010, inf = 0x7fffffff;
bool has[maxn][maxn], flag = 0;
int sum[maxn][maxn], n, m, l[10], r[10], req;
long long ans;
void init() {
  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] + (has[i][j] == 1);
}
int calculate(int x1, int y1, int x2, int y2) {
  return sum[x2][y2] - sum[x1][y2] - sum[x2][y1] + sum[x1][y1];
}
void work(int up, int down, int left, int right, bool dir) {
  if (left == right || up == down) return;
  if (left + 1 == right && up + 1 == down) {
    ans += calculate(up, left, down, right) == req;
    return;
  }
  if (dir == 0) {
    int mid = (left + right) >> 1;
    work(up, down, left, mid, dir ^ 1);
    work(up, down, mid, right, dir ^ 1);
    for (int i = up; i < down; i++) {
      l[0] = r[0] = mid;
      for (int k = 1; k <= req + 1; k++) l[k] = left, r[k] = right;
      for (int j = i + 1; j <= down; j++) {
        for (int k = 1; k <= req + 1; k++)
          while (calculate(i, l[k], j, mid) >= k) l[k]++;
        for (int k = 1; k <= req + 1; k++)
          while (calculate(i, mid, j, r[k]) >= k) r[k]--;
        for (int k = 0; k <= req; k++)
          ans += (l[k] - l[k + 1]) * (r[req - k + 1] - r[req - k]);
      }
    }
  } else {
    int mid = (up + down) >> 1;
    work(up, mid, left, right, dir ^ 1);
    work(mid, down, left, right, dir ^ 1);
    for (int i = left; i < right; i++) {
      l[0] = r[0] = mid;
      for (int k = 1; k <= req + 1; k++) l[k] = up, r[k] = down;
      for (int j = i + 1; j <= right; j++) {
        for (int k = 1; k <= req + 1; k++)
          while (calculate(l[k], i, mid, j) >= k) l[k]++;
        for (int k = 1; k <= req + 1; k++)
          while (calculate(mid, i, r[k], j) >= k) r[k]--;
        for (int k = 0; k <= req; k++)
          ans += (l[k] - l[k + 1]) * (r[req - k + 1] - r[req - k]);
      }
    }
  }
}
int main() {
  while (scanf("%d%d%d", &n, &m, &req) == 3) {
    memset(has, 0, sizeof(has));
    ans = 0;
    for (int i = 1; i <= n; i++)
      for (int j = 1; j <= m; j++) scanf("%1d", &has[i][j]);
    init();
    work(0, n, 0, m, n < m);
    printf("%I64d\n", ans);
  }
  return 0;
}
