#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
int main() {
    int n,m; cin>>n>>m;
    vector<int> k(m);
    int min_k=n;
    for(int _=0;_<n;_++){
    	string s; cin>>s;
    	for(int j=0;j<m;j++) if(s[j]=='o') k[j]++;
    }
	for(int j=0;j<m;j++) min_k=min(min_k, k[j]);
    cout << n-min_k+1<< endl;
    return 0;
}