#include <iostream>
#include <fstream>
#include <cmath>
#include <algorithm>
#include <vector>
#include <set>
#include <map>
#include <stack>
#include <queue>
#include <cstdlib>
#include <cstdio>
#include <string>
#include <cstring>
#include <cassert>
#include <utility>
#include <iomanip>

using namespace std;

const int MAXN = 105000;

int n;
int ans = 0;
stack <int> st;
stack <int> num;
int a[MAXN];

int main() {
	//assert(freopen("input.txt","r",stdin));
	//assert(freopen("output.txt","w",stdout));

	scanf("%d", &n);
	for (int i = 1; i <= n; i++) {
		scanf("%d", &a[i]);
	}

	for (int i = 1; i <= n; i++) {
		if (st.empty()) {
			st.push(a[i]);
			num.push(1);
		}
		else if (st.top() == a[i]) {
			num.top() += 1;
            if (i + 1 > n || a[i + 1] != a[i]) {
            	if (num.top() >= 3) {
            		ans += num.top();
            		st.pop();
            		num.pop();
            	}
            }
		}
		else {
			st.push(a[i]);
			num.push(1);
		}
	}

	printf("%d\n", ans);

	return 0;
}