#include <bits/stdc++.h>
using namespace std;
int32_t main() {
  ios_base::sync_with_stdio(false), cin.tie(NULL), cout.tie(NULL);
  long long n, c;
  cin >> n >> c;
  long long cnt = 0;
  long long ans = 0;
  long long arr[n + 1];
  map<long long, long long> freq, dp;
  for (long long i = 1; i <= n; i++) {
    long long a;
    cin >> a;
    a -= c;
    arr[i] = a;
    if (a == 0) cnt++;
  }
  ans = cnt;
  long long tot = cnt;
  for (long long i = 1; i <= n; i++) {
    if (arr[i] != 0) {
      ans = max(ans, tot + 1LL);
      ans = max(ans, tot + freq[arr[i]] + 1LL - freq[0]);
      if (dp.find(arr[i]) != dp.end()) {
        ans = max(ans, freq[arr[i]] + 1LL - freq[0] + dp[arr[i]] + cnt);
        dp[arr[i]] = max(dp[arr[i]], freq[0] - freq[arr[i]]);
      } else
        dp[arr[i]] = freq[0] - freq[arr[i]];
    }
    freq[arr[i]]++;
  }
  cout << ans;
  return 0;
}
