import java.io.PrintWriter; import java.util.ArrayList; import java.util.Arrays; import java.util.Scanner; public class Main implements Runnable { //Runnableを実装する public static void main(String[] args) { new Thread(null, new Main(), "", 16 * 1024 * 1024).start(); //16MBスタックを確保して実行 } public void run() { Scanner sc=new Scanner(System.in); PrintWriter pw=new PrintWriter(System.out); int N=sc.nextInt(); int M=sc.nextInt(); int[] cnt=new int[M]; for (int i=0;i<N;++i) { char[] cs=sc.next().toCharArray(); for (int j=0;j<cs.length;++j) { if (cs[j]=='x') ++cnt[j]; } } int ans=Arrays.stream(cnt).max().getAsInt()+1; pw.println(ans); pw.close(); } void tr(Object ... o) {System.out.println(Arrays.deepToString(o));} }