#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, k, max = 0, count = 0;
  cin >> n >> k;
  vector<int> v(n);
  for (int i = 0; i < n; i++) {
    cin >> v[i];
    if (v[i - 1] != v[i])
      count++;
    else if (count > max) {
      max = count;
      count = 1;
    } else
      count = 1;
  }
  if (max < count) max = count;
  cout << max;
  return 0;
}
