#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>

using namespace std;

const int N = 60;
int n;
int h[N];
int up[N], down[N];
int ans;

void dfs(int u, int su, int sd)
{
    if (su + sd >= ans) return;

    if (u == n){
        ans = min(ans, su + sd);
        return;
    }

    int k = 0;
    while (k < su && up[k] >= h[u]) k ++ ;
    if (k < su){
        int t = up[k];
        up[k] = h[u];
        dfs(u + 1, su, sd);
        up[k] = t;
    }else{
        up[k] = h[u];
        dfs(u + 1, su + 1, sd);
    }

    k = 0;
    while (k < sd && down[k] <= h[u]) k ++ ;
    if (k < sd){
        int t = down[k];
        down[k] = h[u];
        dfs(u + 1, su, sd);
        down[k] = t;
    }else{
        down[k] = h[u];
        dfs(u + 1, su, sd + 1);
    }
}

int main()
{
    while (cin >> n, n){
        for (int i = 0; i < n; i ++ ) cin >> h[i];
        ans = n;
        dfs(0, 0, 0);
        cout << ans << endl;
    }

    return 0;
}