#include <bits/stdc++.h>
using namespace std;
template <typename T, typename U>
inline void smin(T &a, U b) {
  if (a > b) a = b;
}
template <typename T, typename U>
inline void smax(T &a, U b) {
  if (a < b) a = b;
}
template <class T>
inline void gn(T &first) {
  char c, sg = 0;
  while (c = getchar(), (c > '9' || c < '0') && c != '-')
    ;
  for ((c == '-' ? sg = 1, c = getchar() : 0), first = 0; c >= '0' && c <= '9';
       c = getchar())
    first = (first << 1) + (first << 3) + c - '0';
  if (sg) first = -first;
}
template <class T, class T1>
inline void gn(T &first, T1 &second) {
  gn(first);
  gn(second);
}
template <class T, class T1, class T2>
inline void gn(T &first, T1 &second, T2 &z) {
  gn(first);
  gn(second);
  gn(z);
}
template <class T>
inline void print(T first) {
  if (first < 0) {
    putchar('-');
    return print(-first);
  }
  if (first < 10) {
    putchar('0' + first);
    return;
  }
  print(first / 10);
  putchar(first % 10 + '0');
}
template <class T>
inline void printsp(T first) {
  print(first);
  putchar(' ');
}
template <class T>
inline void println(T first) {
  print(first);
  putchar('\n');
}
template <class T, class U>
inline void print(T first, U second) {
  printsp(first);
  println(second);
}
template <class T, class U, class V>
inline void print(T first, U second, V z) {
  printsp(first);
  printsp(second);
  println(z);
}
int power(int a, int b, int m, int ans = 1) {
  for (; b; b >>= 1, a = 1LL * a * a % m)
    if (b & 1) ans = 1LL * ans * a % m;
  return ans;
}
int n, m, k;
char s[3333][3333];
int cnt[2][3333][3333];
int up[3333], dn[3333];
int calc(int xst, int yst, int xed, int yed, int f) {
  return cnt[f][xed][yed] - cnt[f][xed][yst - 1] - cnt[f][xst - 1][yed] +
         cnt[f][xst - 1][yst - 1];
}
long long solve(int xst, int yst, int xed, int yed, int dir = 0) {
  if (xed - xst < yed - yst) swap(xst, yst), swap(xed, yed), dir ^= 1;
  if (xst == xed) {
    return (calc(xst, yst, xed, yed, dir) == k);
  }
  int mid = xst + xed >> 1;
  long long ans = 0;
  for (int i = yst; i <= yed; i++) {
    for (int j = 0; j <= k + 1; j++) up[j] = xst, dn[j] = xed;
    for (int j = i; j <= yed; j++) {
      for (int p = k; p >= 0; p--) {
        smax(up[i], up[i + 1]);
        smin(dn[i], dn[i + 1]);
        while (calc(up[p], i, mid, j, dir) > p) up[p]++;
        while (calc(mid + 1, i, dn[p], j, dir) > p) dn[p]--;
      }
      for (int p = 0; p <= k; p++) {
        ans += (p ? (up[p - 1] - up[p]) : (mid + 1 - up[p])) *
               (p < k ? (dn[k - p] - dn[k - p - 1]) : (dn[k - p] - mid));
      }
    }
  }
  ans += solve(xst, yst, mid, yed, dir) + solve(mid + 1, yst, xed, yed, dir);
  return ans;
}
int main() {
  gn(n, m, k);
  for (int i = 1; i <= n; i++) {
    scanf("%s", s[i] + 1);
  }
  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= m; j++) {
      s[i][j] -= '0';
      cnt[0][i][j] =
          cnt[0][i - 1][j] + cnt[0][i][j - 1] - cnt[0][i - 1][j - 1] + s[i][j];
      cnt[1][j][i] =
          cnt[1][j - 1][i] + cnt[1][j][i - 1] - cnt[1][j - 1][i - 1] + s[i][j];
    }
  }
  println(solve(1, 1, n, m));
  return 0;
}
