#include <bits/stdc++.h>
using namespace std;
using namespace std::chrono;
template <typename A>
ostream &operator<<(ostream &cout, vector<A> const &v);
template <typename A, typename B>
ostream &operator<<(ostream &cout, pair<A, B> const &p) {
  return cout << "(" << p.first << ", " << p.second << ")";
}
template <typename A>
ostream &operator<<(ostream &cout, vector<A> const &v) {
  cout << "[";
  for (int i = 0; i < v.size(); i++) {
    if (i) cout << ", ";
    cout << v[i];
  }
  return cout << "]";
}
mt19937 rng(steady_clock::now().time_since_epoch().count());
void usaco(string filename) {
#pragma message("be careful, freopen may be wrong")
  freopen((filename + ".in").c_str(), "r", stdin);
  freopen((filename + ".out").c_str(), "w", stdout);
}
const long long mod = 998244353;
long long madd(long long a, long long b) { return (a + b) % mod; }
long long msub(long long a, long long b) {
  return (((a - b) % mod) + mod) % mod;
}
long long mmul(long long a, long long b) {
  return ((a % mod) * (b % mod)) % mod;
}
long long mpow(long long base, long long exp) {
  long long res = 1;
  while (exp) {
    if (exp % 2 == 1) {
      res = (res * base) % mod;
    }
    exp >>= 1;
    base = (base * base) % mod;
  }
  return res;
}
long long minv(long long base) { return mpow(base, mod - 2); }
long long mdiv(long long a, long long b) { return mmul(a, minv(b)); }
long long gcd(long long x, long long y) {
  if (x == 0) return y;
  if (y == 0) return x;
  return gcd(y, x % y);
}
bool isprime(long long n) {
  if (n <= 1) return false;
  if (n <= 3) return true;
  if (n % 2 == 0 || n % 3 == 0) return false;
  for (long long i = 5; i * i <= n; i += 6)
    if (n % i == 0 || n % (i + 2) == 0) return false;
  return true;
}
bool prime[15000105];
void sieve(int n) {
  for (long long i = 0; i < n + 1; i++) prime[i] = 1;
  for (long long p = 2; p * p <= n; p++) {
    if (prime[p] == true) {
      for (long long i = p * p; i <= n; i += p) prime[i] = false;
    }
  }
  prime[1] = prime[0] = 0;
}
vector<long long> primelist;
bool __primes_generated__ = 0;
void genprimes(int n) {
  __primes_generated__ = 1;
  sieve(n + 1);
  for (long long i = 2; i < n + 1; i++)
    if (prime[i]) primelist.push_back(i);
}
vector<int> factors(long long n) {
  if (!__primes_generated__) {
    cerr << "Call genprimes you dope" << endl;
    exit(1);
  }
  vector<int> facs;
  for (long long i = 0;
       primelist[i] * primelist[i] <= n && i < primelist.size(); i++) {
    if (n % primelist[i] == 0) {
      while (n % primelist[i] == 0) {
        n /= primelist[i];
        facs.push_back(primelist[i]);
      }
    }
  }
  if (n > 1) {
    facs.push_back(n);
  }
  sort(facs.begin(), facs.end());
  return facs;
}
long long n, m, k, q, Q, T, l, r, x, y, z;
long long a[1000005];
long long b[1000005];
long long c[1000005];
string second, t;
long long ans = 0;
bool mat[505][505];
int pgrid[505][505];
int psum[505][505];
int main() {
  {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
  };
  cin >> n >> m >> k;
  for (long long i = 0; i < n; i++) {
    cin >> second;
    for (long long j = 0; j < m; j++) {
      mat[i][j] = (second[j] == '1');
    }
  }
  for (long long i = 1; i < n - 1; i++) {
    for (long long j = 1; j < m - 1; j++) {
      bool first = 1;
      first &= mat[i][j];
      first &= mat[i - 1][j];
      first &= mat[i][j - 1];
      first &= mat[i + 1][j];
      first &= mat[i][j + 1];
      pgrid[i][j] = first;
      psum[i + 1][j + 1] =
          pgrid[i][j] + psum[i + 1][j] + psum[i][j + 1] - psum[i][j];
    }
  }
  for (long long i = 1; i < n - 1; i++) {
    for (long long j = i; j < n - 1; j++) {
      int pt = 1;
      long long sum = 0;
      for (long long c = 1; c < m - 1; c++) {
        sum +=
            psum[j + 1][c + 1] - psum[i][c + 1] - psum[j + 1][c] + psum[i][c];
        while (pt < m - 1 && sum >= k) {
          sum -= psum[j + 1][pt + 1] - psum[i][pt + 1] - psum[j + 1][pt] +
                 psum[i][pt];
          ++pt;
        }
        ans += pt - 1;
      }
    }
  }
  cout << ans << endl;
}
