#include <algorithm>
#include <iostream>
#include <vector>
using namespace std;
int main() {
int n,m,k;
cin>>n>>m>>k;
vector<vector<char>> grid(n,vector<char>(m));
for(int i=0;i<n;i++){
for(int j=0;j<m;j++){
cin>>grid[i][j];
}
}
vector<int> couts;
for(int j=0;j<m;j++){
int cnt=0;
for(int i=0;i<n;i++){
if(grid[i][j]=='*'){
if(cnt !=0)
couts.push_back(cnt);
cnt=0;
}
else cnt++;
}
if(cnt !=0)
couts.push_back(cnt);
}
sort(couts.begin(), couts.end(), greater<>());
int score=0;
for(int e:couts){
int c=min(k,e);
score+=c-1;
k-=c;
if(k<=0) break;
}
cout<<score<<endl;
return 0;
}
// 64 位输出请用 printf("%lld")