#include <vector>
#include<iostream>
#include <algorithm>
#include <cmath>
#include <iomanip>
#include <fstream>
#include <string>
#include <set>
#include <deque>
#include <queue>
#include <map>
#include <bitset>
#include <random>
#include <cassert>
#include <unordered_map>
#include <unordered_set>
#include<math.h>
using namespace std;
typedef unsigned int ui;
typedef long long             ll;
typedef unsigned long long     ull;
typedef long double            ld;
#define endl              "\n"
#define all(a)            a.begin(), a.end()
#define allr(a)           a.rbegin(), a.rend()
#define pb                push_back
#define pikachu           push_back
#define F                 first
#define S                 second

void solve() {

}
ll a[301][301];
ll pref[301][301];
void count(ll n, ll m) {
    pref[0][0] = a[0][0];
    for (ll i = 1; i < n; i++)
        pref[i][0] = pref[i - 1][0] + a[i][0];
    for (ll i = 1; i < m; i++)
        pref[0][i] = pref[0][i - 1] + a[0][i];
    for (ll i = 1; i < n; i++)
        for (ll j = 1; j < m; j++)
            pref[i][j] = pref[i - 1][j] + pref[i][j - 1] - pref[i - 1][j - 1] + a[i][j];
}
ll qq(ll x1, ll y1, ll x2, ll y2) {
    return pref[x2][y2] - (x1 ? pref[x1 - 1][y2] : 0) - (y1 ? pref[x2][y1 - 1] : 0) + (x1 && y1 ? pref[x1 - 1][y1 - 1] : 0);
}
signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    ll t = 1;
    //cin >> t;
    //cout << fixed << setprecision(18);
    while (t--) {
        ll n, m, s, k;
        cin >> n >> m >> k >> s;
        for (ll i = 0; i < n; i++) {
            string s;
            cin >> s;
            for (ll j = 0; j < m; j++) {
                if (s[j] == '#') {
                    a[i][j] = 1;
                }
                else {
                    a[i][j] = 0;
                }
            }
        }
        count(n, m);
        ll ans = 0;
        for (ll i = 0; i < n; i++) {
            if ((i + 1) * m < s)continue;
            for (ll j = 0; j < m; j++) {
                if ((i + 1) * (j + 1) < s) {
                    continue;
                }
                for (ll x = 0; x <= i; x++) {
                    if ((i - x + 1) * (j + 1) < s)break;
                    for (ll y = 0; y <= j; y++) {
                        if ((i - x + 1) * (j - y + 1) < s)break;;
                        if (qq(x, y, i, j) <= k) {
                            ans++;
                        }
                    }
                }
            }
        }
        cout << ans << endl;
    }
}