#include <iostream>
#include <vector>
#define ll long long
using namespace std;
ll r,c,d,k,to=0;
vector<vector<ll>> mp;
vector<string> tmp;
void set(int y,int x,int d)
{
int tly = max(y-d,1),tlx = max(x-d,1);
int bry = min(y+d,(int)r),brx = min(x+d,(int)c);
//cout<<tly<<" "<<tlx<<" "<<bry<<" "<<brx<<"\n";
mp[tly][tlx] ++;
mp[tly][brx+1] --;
mp[bry+1][tlx] --;
mp[bry+1][brx+1] ++;
}
int main()
{
cin>>r>>c>>d>>k;
for (int i=0;i<r+2;i++)
{
mp.push_back(vector<ll>());
for (int j=0;j<c+2;j++)
{
mp[i].push_back(0);
}
}
string trsh = "";
for (int i=0;i<c;i++)
{
trsh+=" ";
}
tmp.push_back(trsh);
for (int i=0;i<r;i++)
{
string tp;cin>>tp;
tp=" "+tp;tp+=" ";
tmp.push_back(tp);
}
tmp.push_back(trsh);
for (int i=1;i<=r;i++)
{
for (int j=1;j<=c;j++)
{
if (tmp[i][j]=='S') {set(i,j,d);}
}
}
for (int i=1;i<=r;i++)
{
for (int j=1;j<=c;j++)
{
mp[i][j] += mp[i-1][j] + mp[i][j-1] - mp[i-1][j-1];
if (tmp[i][j]=='M'&&mp[i][j]>=k) {to++;}
}
}
cout<<to<<"\n";
return 0;
}
