#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
#define MASK(i) (1LL << (i))
#define GETBIT(mask, i) (((mask) >> (i)) & 1)
#define ALL(v) (v).begin(), (v).end()
ll max(ll a, ll b){return (a > b) ? a : b;}
ll min(ll a, ll b){return (a < b) ? a : b;}
ll gcd(ll a, ll b){return __gcd(a, b);}
ll LASTBIT(ll mask){return (mask) & (-mask);}
int pop_cnt(ll mask){return __builtin_popcountll(mask);}
int ctz(ll mask){return __builtin_ctzll(mask);}
int logOf(ll mask){return __lg(mask);}
mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
ll rngesus(ll l, ll r){return l + (ull) rng() % (r - l + 1);}
template <class T1, class T2>
bool maximize(T1 &a, T2 b){
if (a < b) {a = b; return true;}
return false;
}
template <class T1, class T2>
bool minimize(T1 &a, T2 b){
if (a > b) {a = b; return true;}
return false;
}
template <class T>
void printArr(T& container, string separator = " ", string finish = "\n"){
for(auto item: container) cout << item << separator;
cout << finish;
}
template <class T>
void remove_dup(vector<T> &a){
sort(ALL(a));
a.resize(unique(ALL(a)) - a.begin());
}
void solve(){
int n, m, d, k; cin >> n >> m >>d >> k;
vector<string> grid(n+1);
for(int i = 1; i<= n; ++i){
cin >> grid[i];
grid[i] = "." + grid[i];
}
int sum[n+2][m+2]; memset(sum, 0, sizeof sum);
for(int i = 1; i<= n; ++i) for(int j= 1; j <= m; ++j) if (grid[i][j] == 'S'){
int u = i - d, v = j - d, x = i + d, y = j + d;
minimize(x, n); minimize(y, m);
maximize(u, 1); maximize(v, 1);
sum[u][v]++;
sum[u][y+1]--;
sum[x+1][v]--;
sum[x+1][y+1]++;
}
int ans = 0;
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];
if (sum[i][j] >= k && grid[i][j] == 'M') ans++;
}
cout << ans << "\n";
}
int main(void){
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
clock_t start = clock();
solve();
cerr << "Time elapsed: " << clock() - start << "ms!\n";
return 0;
}
