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// {{{
#define _USE_MATH_DEFINES
#include <bits/stdc++.h>

#define each(...)    for (auto& __VA_ARGS__)
#define rep(i, b, e) for (int i = (b); i <= (e); i++)
#define rev(i, b, e) for (int i = (e); i >= (b); i--)
#define mp make_pair
#define mt make_tuple
#define x first
#define y second
#define pb push_back
#define all(x) (x).begin(), (x).end()
#ifdef SPONGE
#define dbg(f, ...) fprintf(stderr, "\033[1;33m" f "\033[0m", ##__VA_ARGS__)
#else
#define dbg(...) 1
#endif
#define tC template<class

using namespace std;

tC T> using V = vector<T>;
tC T1, class T2> using P = pair<T1,T2>;
tC T, class C=greater<T>> using PQ = priority_queue<T,V<T>,C>;

using ll = long long;
using ld = long double;
using ul = unsigned long long;
using pii = P<int,int>;
using pll = P<ll,ll>;
using pld = P<ld,ld>;
using vi = V<int>;
using vll = V<ll>;
using vld = V<ld>;
using vb = V<bool>;
using vs = V<string>;
using vpii = V<pii>;
using vpll = V<pll>;
using vpld = V<pld>;

tC T> int sz(const T& a) { return (int)a.size(); }
tC T> bool amin(T& a, T b) { return b < a ? a = b, 1 : 0; }
tC T> bool amax(T& a, T b) { return b > a ? a = b, 1 : 0; }

const size_t rseed = 4488;
// chrono::high_resolution_clock::now().time_since_epoch().count();
mt19937 rnd(rseed);
tC T> T rand(T lo, T hi) { return uniform_int_distribution<T>{lo,hi}(rnd); }

const int oo = 1e9 + 1;
const ll OO = 1e18 + 1;

namespace { void solve(); }
// }}}

int main()
{
  int t = 1;
  // scanf("%d", &t);
  rep(i, 1, t) {
    // printf("Case #%d: ", i);
    solve();
  }
}

namespace {

const int N = 5e4 + 15;
int n, a[N];

// 0 - zjazd, 1 - wjazd
int dp[N][2], odp = oo;

void solve()
{
  scanf("%d", &n);
  rep(i, 1, n) {
    scanf("%d", &a[i]);
  }

  rep(i, 2, n) {
    rep(j, 0, 1) dp[i][j] = dp[i - 2][j] + 1;
    if (a[i - 1] < a[i]) {
      amin(dp[i][1], dp[i - 1][0]);
    }
    else if (a[i - 1] > a[i]) {
      amin(dp[i][0], dp[i - 1][1]);
    }
  }

  rep(j, 0, 1) amin(odp, dp[n][j]);
  printf("%d\n", odp);
}

}