#include <bits/stdc++.h>
#define ll long long
#define pii pair<int,int>
using namespace std;
const int MAX=100005;
int N=6;
int A[MAX]={1,2,3,2,1,3};
int P[MAX];
int L[MAX];
int R[MAX];
bool done=false;
vector<int> roots;
vector<int> new_roots;
void resolve(int i, int x){
if (A[i]==x){
if (L[i]!=-1) resolve(L[i],x);
if (R[i]!=-1) resolve(R[i],x);
}else{
new_roots.push_back(i);
}
}
int main(){
//*
cin>>N;
for (int i=0;i<N;i++) cin>>A[i];/**/
for (int i=0;i<N;i++){
L[i]=-1,R[i]=-1,P[i]=-1;
}
int root=0;
for (int i=1;i<N;i++){
int x=i-1;
while (x!=-1&&A[x]>=A[i]) x=P[x];
if (x==-1) L[i]=root, P[root]=i, root=i;
else{
P[i]=x;
if (R[x]==-1) R[x]=i;
else L[i]=R[x], P[R[x]]=i, R[x]=i;
}
}
roots.push_back(root);
int ans=0;
while (roots.size()){
new_roots.clear();
for (auto r: roots){
ans++;
resolve(r, A[r]);
}
roots.clear();
for (auto r: new_roots){
roots.push_back(r);
}
}
cout<<ans;
}
