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#include <bits/stdc++.h>

using namespace std;

int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    int n;
    cin >> n;

    vector <int> a(n);
    for(int i = 0; i < n; i++) cin >> a[i];

    vector <vector<vector<int>>> dp(n, vector<vector<int>>(2, vector<int>(2)));
    dp[0][0][0] = 0;
    dp[0][1][0] = 1;
    dp[0][0][1] = 0;
    dp[0][1][1] = 1;

    for(int i = 1; i < n; i++){
        for(int k = 0; k < 2; k++){
            dp[i][1][k] = min(dp[i-1][0][k], dp[i-1][1][k]) + 1;
            if(((k+i)%2 == 0 && a[i] > a[i-1]) || ((k+i)%2 == 1 && a[i] < a[i-1])) dp[i][0][k] = min(dp[i-1][0][k], dp[i-1][1][k]);
            else dp[i][0][k] = dp[i-1][1][k];
        }
    }

    cout << min({dp[n-1][0][0], dp[n-1][1][0], dp[n-1][0][1], dp[n-1][1][1]}) << "\n";

    return 0;
}