#include <bits/stdc++.h>
using namespace std;
int n, a[109], dp[109][2];
int main() {
    scanf("%d", &n);
    for(int i = 0; i < n; i++) scanf("%d", &a[i]);
    for(int i = 0; i < n; i++) {
        dp[i][0] = dp[i][1] = 1;
        for(int j = 0; j < i; j++) {
            if(a[j] > a[i]) dp[i][0] = max(dp[i][0], dp[j][1] + 1);
            if(a[j] < a[i]) dp[i][1] = max(dp[i][1], dp[j][0] + 1);
        }
    }
    cout << n - max(dp[n - 1][0], dp[n - 1][1]) << endl;
    return 0;
}

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6
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