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#include <bits/stdc++.h>
using namespace std;

int dp[2][2][50100];
int a[50100];

void solve() {
    int n;
    cin >> n;
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
    }
    // 0 decline
    // 1 incline
    dp[0][0][1] = 0;
    dp[1][0][1] = 0;
    dp[0][1][1] = 1;
    dp[1][1][1] = 1;
    for (int i = 2; i <= n; i++) {
        dp[0][0][i] = dp[1][0][i] = dp[0][1][i] = dp[1][1][i] = 1e9;
        // make decline
        dp[0][0][i] = min(dp[0][0][i], dp[1][1][i-1]);
        if (a[i-1] > a[i])
            dp[0][0][i] = min(dp[0][0][i], dp[1][0][i-1]);
        dp[0][1][i] = min(dp[0][1][i], min(dp[1][0][i-1], dp[1][1][i-1])+1);
        // make incline
        dp[1][0][i] = min(dp[1][0][i], dp[0][1][i-1]);
        if (a[i-1] < a[i])
            dp[1][0][i] = min(dp[1][0][i], dp[0][0][i-1]);
        dp[1][1][i] = min(dp[1][1][i], min(dp[0][0][i-1], dp[0][1][i-1])+1);
    }
    cout << min({dp[0][0][n], dp[0][1][n], dp[1][0][n], dp[1][1][n]}) << "\n";
}

int main(){

    ios_base::sync_with_stdio(0);
    cin.tie(0);

    int t;
    t = 1;

    #ifdef Local
        // freopen("input.txt", "r", stdin);
        // freopen("output.txt", "w", stdout);
        // cin >> t;
    #endif
    // cin >> t;
    
    while(t--){
        solve();
    }


    return 0;
}