#include <iostream>

using namespace std;

int l[1000005];
int n;
void solve() {
  cin >> n;
  for(int i = 0; i < n; i++) cin >> l[i];
  int ret = -1;
  for(int i = 0; i < n; i++) {
    int a = i-1;
    int b = i+1;
    int curr = 1;
    while(a >= 0 && b < n && l[a] == l[b] && l[a] < l[a+1]) {
      curr += 2;
      a--;
      b++;
    }
    if(curr > 1) ret = max(ret, curr);
  }
  cout << ret << "\n";
}

int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  solve();
}