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#pragma GCC optimize ("O3")
#include <bits/stdc++.h>
using namespace std;

#define FOR(i, b, e) for(int i = (b); i < (e); i++)
#define TRAV(x, v) for(auto &x: v)
#define PB push_back
#define SZ(x) ((int)x.size())
#define X first
#define Y second

using ll = long long;
using vi = vector<int>;
using ii = pair<int, int>;
constexpr int INF = 0x3f3f3f3f;

int licz(vi vec, bool how) {
    int last = (how ? INF : -INF);
    int res = 0;
    TRAV(x, vec) {
        if(how) {   // maleje
            if(x >= last) res++, last = -INF;
            else last = x;
        }
        else {  // rosnie
            if(x <= last) res++, last = INF;
            else last = x;
        }
        how ^= 1;
    }
    return res;
}

void solve() {
    int n;
    cin >> n;
    vi vec(n);
    TRAV(x, vec) cin >> x;
    cout << min(licz(vec, 0), licz(vec, 1)) << '\n';
}

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    // int tt; cin >> tt;
    // FOR(te, 0, tt) {
    //     // cout << "Case #" << te + 1 << ": ";
    //     solve();
    // }
    solve();
    return 0;
}