///yl/hs/bx/yl
#include<bits/stdc++.h>
#define fep(i,l,r) for(int i=l;i<=r;++i)
#define feb(i,r,l) for(int i=r;i>=l;--i)
#define For(i,u) for(int i=head[u];i;i=e[i].nxt)
#define LL long long
// #define int long long
#define ld long double
#define pr pair<int,int>
#define mpr make_pair
using namespace std;

const int N = 1e6+5,mod = 1e9+7;
inline int read()
{
   int s=0,w=1; char ch=getchar();
   while(!(ch>='0'&&ch<='9')) {if(ch=='-') w=-1; ch=getchar();}
   while(  ch>='0'&&ch<='9')  {s=(s<<1)+(s<<3)+ch-'0'; ch=getchar();}
   return s*w;
}
inline int Mod(int x) {return x>=mod?x-mod:x;}
inline void addmod(int &x,int y) {x=Mod(x+y);}

namespace starrylasky
{
    int n,a[N];
    inline void Main()
    {
        n=read();
        fep(i,1,n)
        {
            int x=read(); if(x==a[i-1]) --i,--n;
            a[i]=x;
        }
        int cnt=0;
        fep(i,1,n) if(a[i-1]<a[i]&&a[i]>a[i+1]) ++cnt;
        // cerr<<cnt<<"\n";
        printf("%d\n",cnt==1&&a[n]>a[n-1]?0:((int)ceil(log2(cnt))+1));
    }
}

signed main()
{
    int _T=1;
    while(_T--) starrylasky::Main();
    return 0;
}