#include <iostream>
#include <vector>
using namespace std;
#define ll long long
#define MIN(a, b) (((a) < (b)) ? (a) : (b))
#define MAX(a, b) (((a) < (b)) ? (b) : (a))
vector<vector<char>> v;
vector<vector<int>> sum;
int main()
{
int n, m, d, k;
cin >> n >> m >> d >> k;
v.resize(2 + n);
for(int i = 0; i <= n + 1; i++)
v[i].resize(2 + m);
sum.resize(2 + n);
for(int i = 0; i <= n + 1; i++)
sum[i].resize(2 + m);
for(int i = 1;i <= n; i++)
for(int j = 1;j <= m; j++) {
cin >> v[i][j];
if(v[i][j] == 'S'){
int x = max(1, i - d);
int y = max(1, j - d);
int x2 = min(1 + n, 1 + i + d);
int y2 = min(1 + m, 1 + j + d);
sum[x][y]++;
sum[x][y2]--;
sum[x2][y]--;
sum[x2][y2]++;
}
}
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];
}
}
int result = 0;
for(int i = 1;i <= n; i++)
for(int j = 1; j <= m; j++)
if(k <= sum[i][j] && v[i][j] == 'M')
result++;
cout << result;
return 0;
}
