#include <bits/stdc++.h>
using namespace std;
#define boost ios_base::sync_with_stdio(0);
#define ll int
#define pb push_back
#define tc long long int t; cin >> t; while(t--)
#define vpll vector<pair<ll,ll>>
#define MOD 1000000007
int main(){
boost;
ll i;
ll r,c,d,k;
cin >> r >> c >> d >> k;
char a[r+1][c+1];
ll diff[r+1][c+1];
ll pre[r+1][c+1];
ll j;
for(i = 1; i <= r; i++){
for(j = 1; j <= c; j++){
cin >> a[i][j];
if(a[i][j] == 'S'){
diff[i][j] = 1;
}
else{
diff[i][j] = 0;
}
}
}
for(i= 0 ; i<= r; i++){
for(j = 0; j <= c; j++){
pre[i][j] = 0;
}
}
/*for(i = 0; i <= r; i++){
diff[i][0] = 0;
}
for(j = 0; j <= c; j++){
diff[0][j] = 0;
}
pre[1][1] = diff[1][1];
for(i = 1; i <= r; i++){
pre[i][0] = pre[i-1][0] + diff[i][0];
}
for(i = 1; i < c; i++){
pre[0][i] = pre[0][i-1] + diff[0][i];
}*/
for(i = 1; i <= r; i++){
for(j = 1; j <= c; j++){
pre[i][j] = (diff[i][j] + pre[i-1][j] + pre[i][j-1]) - pre[i-1][j-1];
//cout << "1" <<endl;
}
}
ll u,v,x,y, ans = 0;;
/*for(i = 0; i < r; i++){
for(j = 0; j < c; j++){
cout << pre[i][j] << " ";
}
cout << endl;
}*/
for(i = 1; i <= r; i++){
for(j = 1; j <= c; j++){
if(a[i][j] == 'M'){
u = max(1,i-d);
v = max(1,j-d);
x = min(r, i+d);
y = min(c, j+d);
ll temp = pre[x][y] - pre[u-1][y] - pre[x][v-1] + pre[u-1][v-1];
if(temp >= k){
ans++;
//cout << "i " << i << " j " << j <<endl;
}
}
//cout << "1" << endl;
}
}
cout << ans <<endl;
return 0;
}
