/**
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**/
#define _FORTIFY_SOURCE 0
#pragma GCC optimize("Ofast")
#pragma GCC optimize("no-stack-protector")
#pragma GCC optimize("unroll-loops")
#pragma GCC target("sse,sse2,sse3,ssse3,popcnt,abm,mmx,tune=native")
#pragma GCC optimize("fast-math")
#include <iostream>
#include <string>                 
#include <stdio.h>
#include <vector>
#include <set>
#include <unordered_set>
#include <map>
#include <unordered_map>
#include <deque>
#include <algorithm>
#include <math.h>
#include <time.h>
#include <random>
#define ff first
#define ss second
#define pb push_back
#define mp make_pair
#define int long long
#define double long double
#define left left228
#define right right228 
#define x1 x1228 
#define y1 y1228
#define all(x) x.begin(), x.end()
       
using namespace std;
       
typedef long long ll;
typedef pair<int, int> pii;
mt19937 rnd(time(0));
                                                      
const int maxn = 3e5 + 7, mod = 1e9 + 7, inf = 1e18;
const double eps = 1e-9, pi = acos(-1);
int n, cnt[maxn];
	        
void solve() {
	cin >> n;
	cnt[n] = inf; 
	for (int i = 0; i < n; ++i) cin >> cnt[i];
	int ans = 0;
	for (int i = 1; i < n; ++i) {
		if (cnt[i] == cnt[i - 1]) {
			int val;
			++ans;
			while (true) {
				val = rnd() % 10000 + 1;
				if (val != cnt[i - 1] && val != cnt[i + 1]) {
					cnt[i] = val; 
					break; 
				}
			}
		}		
	}
	cout << ans;	
}                                
   
signed main() {
//  freopen("string.in", "r", stdin);
//  freopen("string.out", "w", stdout);
    #ifdef offline_judge
        freopen("TASK.in", "r", stdin);
        freopen("TASK.out", "w", stdout);
    #endif      
    srand(time(0)); 
    cout.precision(10);
    cout << fixed;
    ios_base::sync_with_stdio(false);
    cin.tie(0); 
    solve();
    return 0;                                        
}

Measured memory_bytes: 256