#include <iostream>
using namespace std;
int main() {
int n, d, y=0;
cin >> n >> d;
char ara[n][d];
for(int i=0; i<n; i++){
for(int j=0; j<d; j++){
cin >> ara[i][j];
}
}
for(int j=0; j<d; j++){
int x=0;
for(int i=0; i<n; i++){
if(ara[i][j] == 'o')
x++;
}
if(x == n)
y++;
}
cout << y;
return 0;
}
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