#include"bits/stdc++.h"
using namespace std;
#define REP(k,m,n) for(int (k)=(m);(k)<(n);(k)++)
#define rep(i,n) REP((i),0,(n))
using ll = long long;

int main()
{
    int N;
    cin >> N;
    vector<int> A(N), B;
    vector<bool> same(N, false);
    rep(i, N)cin >> A[i];

    rep(i, N - 1) {
        if (A[i] == A[i + 1]) {
            same[i] = same[i + 1] = true;
        }
    }
    {
        int cnt = 0;
        rep(i, N) {
            if (same[i]) {
                if (cnt != 0)B.push_back(cnt);
                cnt = 0;
            }
            else {
                cnt++;
            }
        }
        if (cnt != 0)B.push_back(cnt);
    }


    int res = count(same.begin(), same.end(), true);
    if (!same.front() && !same.back() && B.size() == 1) {
        res += (B.front() + 1) / 2;
        B.pop_back();
    }
    if (!same.front() && !B.empty()) {
        res += B.front() / 2;
        B.erase(B.begin());
    }
    if (!same.back() && !B.empty()) {
        res += B.back() / 2;
        B.pop_back();
    }
    for (int len : B) {
        res += (len - 1) / 2;
    }
    cout << res << endl;
    return 0;
}