#include <bits/stdc++.h>
#define int long long
int r,c,d,k;
std::vector<std::vector<int>> grid;
std::vector<std::vector<int>> dp;
std::vector<std::vector<bool>> mark;
signed main() {
std::ios::sync_with_stdio(false);
std::cin.tie(nullptr);
std::cin >> r >> c >> d >> k;
grid.resize(r+2);dp.resize(r+2);mark.resize(r+2);
for(auto& v:grid)v.resize(c+2);
for(auto& v:dp)v.resize(c+2);
for(auto& v:mark)v.resize(c+2);
for(int i=1;i<=r;i++){
std::string in;
std::cin >> in;
for(int j=1;j<=c;j++){
if(in[j-1]=='M')mark[i][j]=true;
if(in[j-1]=='S'){
dp[std::max((int)1,i-d)][std::max((int)1,j-d)]+=1;
dp[std::max((int)1,i-d)][std::min(c+1,j+d+1)]-=1;
dp[std::min(r+1,i+d+1)][std::max((int)1,j-d)]-=1;
dp[std::min(r+1,i+d+1)][std::min(c+1,j+d+1)]+=1;
}
}
}
int cnt=0;
for(int i=1;i<=r;i++){
for(int j=1;j<=c;j++){
grid[i][j]=grid[i-1][j]+grid[i][j-1]-grid[i-1][j-1]+dp[i][j];
//std::cout << grid[i][j] << ' ';
if(mark[i][j]&&grid[i][j]>=k)cnt+=1;
}
//std::cout << '\n';
}
std::cout << cnt;
}
