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/*
    Jakub Żojdzik
    12-12-2022
*/

#include <bits/stdc++.h>
#ifdef LOCAL
#include "debug.hpp"
#else
#define debug(...)
#define dt
#endif
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef double db;
typedef pair<int, int> pii;
typedef pair<long long, long long> pll;
typedef vector<int> vi;
typedef vector<long long> vll;
typedef vector<pair<int, int>> vpii;
typedef vector<pair<long long, long long>> vpll;

#define fi first
#define se second
#define pb push_back
#define rep(i, x, y) for(ll i = (ll)x; i <= (ll)y; i++)
#define all(x) x.begin(), x.end()
#define sz(x) (ll)(x).size()
#define nl cout << '\n'

ll tab[50007];

int main()
{
    cout.tie(0);
    cin.tie(0)->sync_with_stdio(0);

    ll n;
    cin >> n;
    rep(i, 0, n-1)
    {
        cin >> tab[i];
    }

    bool wiekszy = 1;
    ll popr = -1e9, res1 = 0;
    rep(i, 0, n-1)
    {
        if(wiekszy && tab[i] <= popr)
        {
            res1++;
            popr = 1e9;
        }
        else if((!wiekszy) && tab[i] >= popr)
        {
            res1++;
            popr = -1e9;
        }
        else
        {
            popr = tab[i];
        }
        wiekszy = !wiekszy;
    }

    wiekszy = 0;
    popr = 1e9;
    ll res2 = 0;
    rep(i, 0, n-1)
    {
        if(wiekszy && tab[i] <= popr)
        {
            res2++;
            popr = 1e9;
        }
        else if((!wiekszy) && tab[i] >= popr)
        {
            res2++;
            popr = -1e9;
        }
        else
        {
            popr = tab[i];
        }
        wiekszy = !wiekszy;
    }

    cout << min(res1, res2) << '\n';
}

/*

*/