#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define endl "\n"

queue<ll> que;
ll t[10086],cnt,ci;
int main(){
	ll n;
	cin >> n;
	for(ll i = 1; i<= n;i++){
		ll temp;
		cin >> temp;
		que.push(temp);
	}
	while(cnt < n){
		ci++;
		ll tp = que.front();
		que.pop();
		if(tp != que.front() || que.front() == -1 || tp == -1){
			cnt++;
			que.pop();
			que.push(-1);
		}else{
			que.push(tp);
		}
		if(ci >= 1e6){
			cout << 0;
			return 0;
		}
	}
	cout << cnt-1;

}

玄关