#include <bits/stdc++.h>
using namespace std;
template <typename _T>
inline void read(_T &f) {
  f = 0;
  _T fu = 1;
  char c = getchar();
  while (c < '0' || c > '9') {
    if (c == '-') fu = -1;
    c = getchar();
  }
  while (c >= '0' && c <= '9') {
    f = (f << 3) + (f << 1) + (c & 15);
    c = getchar();
  }
  f *= fu;
}
template <typename T>
void print(T x) {
  if (x < 0) putchar('-'), x = -x;
  if (x < 10)
    putchar(x + 48);
  else
    print(x / 10), putchar(x % 10 + 48);
}
template <typename T>
void print(T x, char t) {
  print(x);
  putchar(t);
}
template <typename T>
struct hash_map_t {
  vector<T> v, val, nxt;
  vector<int> head;
  int mod, tot, lastv;
  T lastans;
  bool have_ans;
  hash_map_t(int md = 0) {
    head.clear();
    v.clear();
    val.clear();
    nxt.clear();
    tot = 0;
    mod = md;
    nxt.resize(1);
    v.resize(1);
    val.resize(1);
    head.resize(mod);
    have_ans = 0;
  }
  void clear() { *this = hash_map_t(mod); }
  bool count(int x) {
    int u = x % mod;
    for (register int i = head[u]; i; i = nxt[i]) {
      if (v[i] == x) {
        have_ans = 1;
        lastv = x;
        lastans = val[i];
        return 1;
      }
    }
    return 0;
  }
  void ins(int x, int y) {
    int u = x % mod;
    nxt.push_back(head[u]);
    head[u] = ++tot;
    v.push_back(x);
    val.push_back(y);
  }
  int qry(int x) {
    if (have_ans && lastv == x) return lastans;
    count(x);
    return lastans;
  }
};
const int N = 2505;
int s[N][N], mx[N], mn[N];
char c[N][N];
int n, m, k;
long long ans;
inline int calc(int x, int y, int _x, int _y) {
  if (x > _x || y > _y) return 0;
  return s[_x][_y] - s[_x][y - 1] - s[x - 1][_y] + s[x - 1][y - 1];
}
void solve(int x, int y, int _x, int _y) {
  if (x == _x || y == _y) return;
  if (_x - x == 1 && _y - y == 1) {
    if (calc(x + 1, y + 1, _x, _y) == k) ++ans;
    return;
  }
  if (_x - x >= _y - y) {
    int mid = (x + _x) >> 1;
    solve(x, y, mid, _y);
    solve(mid, y, _x, _y);
    for (register int i = y + 1; i <= _y; i++) {
      mn[0] = mx[0] = mid;
      for (register int j = 1; j <= k + 1; j++) mn[j] = x, mx[j] = _x;
      for (register int j = i; j <= _y; j++) {
        for (register int t = 1; t <= k + 1; t++) {
          while (calc(mn[t] + 1, i, mid, j) >= t) ++mn[t];
          while (calc(mid + 1, i, mx[t], j) >= t) --mx[t];
        }
        for (register int t = 0; t <= k; t++) {
          ans += (mn[t] - mn[t + 1]) * (mx[k - t + 1] - mx[k - t]);
        }
      }
    }
  } else {
    int mid = (y + _y) >> 1;
    solve(x, y, _x, mid);
    solve(x, mid, _x, _y);
    for (register int i = x + 1; i <= _x; i++) {
      mn[0] = mx[0] = mid;
      for (register int j = 1; j <= k + 1; j++) mn[j] = y, mx[j] = _y;
      for (register int j = i; j <= _x; j++) {
        for (register int t = 1; t <= k + 1; t++) {
          while (calc(i, mn[t] + 1, j, mid) >= t) ++mn[t];
          while (calc(i, mid + 1, j, mx[t]) >= t) --mx[t];
        }
        for (register int t = 0; t <= k; t++) {
          ans += (mn[t] - mn[t + 1]) * (mx[k - t + 1] - mx[k - t]);
        }
      }
    }
  }
}
int main() {
  read(n);
  read(m);
  read(k);
  for (register int i = 1; i <= n; i++) {
    scanf("%s", c[i] + 1);
    for (register int j = 1; j <= m; j++) {
      s[i][j] = s[i - 1][j] + s[i][j - 1] - s[i - 1][j - 1] + c[i][j] - '0';
    }
  }
  solve(0, 0, n, m);
  print(ans, '\n');
  return 0;
}
