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#include<bits/stdc++.h>

using namespace std;
#define nd second
#define st first
#define pb push_back
typedef long long ll;
typedef long double ld;
const int N = 50 * 1000 + 7;
int dp[2][2][N];
int tab[N];

void Solve()
{
    int n, w;
    cin >> n;
    for(int i = 1; i <= n; ++i)
        cin >> tab[i];
    dp[1][0][1] = 0; dp[1][1][1] = 1;
    dp[0][0][1] = 0; dp[0][1][1] = 1;
    for(int i = 2; i <= n; ++i)
    {
        dp[0][0][i] = dp[1][1][i - 1];
        if(tab[i] < tab[i - 1]) dp[0][0][i] = min(dp[1][0][i - 1], dp[1][0][i - 1]);
        dp[0][1][i] = min(dp[1][0][i - 1], dp[1][1][i - 1]) + 1;
        dp[1][0][i] = dp[0][1][i - 1];
        if(tab[i] > tab[i - 1]) dp[1][0][i] = min(dp[0][0][i - 1], dp[0][0][i - 1]);
        dp[1][1][i] = min(dp[0][0][i - 1], dp[0][1][i - 1]) + 1;
        //cout << dp[0][0][i] << " " << dp[0][1][i] << " " << dp[1][0][i] << " " << dp[1][1][i] << "\n";
    }
    w = min(min(dp[0][1][n], dp[0][0][n]), min(dp[1][1][n], dp[1][0][n]));
    cout << w << "\n";
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    Solve();

    return 0;
}