#include <iostream>
#include <vector>
#include <cmath>
#include <map>
#include <set>
#include <iomanip>
#include <queue>
#include <algorithm>
#include <numeric>
#include <deque>
#include <complex>
#include <cassert>

using namespace std;
using ll = long long;

int main(){

    int H, W, ans=0, cnt=0;
    cin >> H >> W;
    vector<string> S(H);
    for (int i=0; i<H; i++) cin >> S[i];

    for (int j=0; j<W; j++){
        cnt = 0;
        for (int i=0; i<H; i++){
            if (S[i][j] == 'x') cnt++;
        }
        ans = max(ans, cnt);
    }

    cout << cnt+1 << endl;

    return 0;
}