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#include <bits/stdc++.h>
typedef long long ll;
using namespace std;
const ll inf = 1e18 + 7;
const ll mod = 1e9 + 7;
ll n , m , k , ans = 0 , q;
ll dp[50005][2][2];
// ifstream in , out;
int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
  /*  for (int t = 5; t < 1000; t++) {
        string sin = "orn" , sout = "orn" , st = "";
        ll kop = t;
        while (kop > 0) {
           st += char(kop % 10 + 48);
           kop /= 10;
        }
        if (st.size() == 0)st = "0";
        reverse(st.begin() , st.end());
        sin += st;
        sout += st;
        sin += ".in";
        sout += ".out";
        cout << sin << endl;
        in.open(sin);
        out.open(sout); */
    cin >> n;
    vector<ll>vec(n + 1);
    for (int i = 1; i <= n; i++) {
          cin >> vec[i];
    }
    dp[1][0][0] = dp[1][1][0] = 0;
    dp[1][0][1] = dp[1][1][1] = 1;
    for (int i = 2; i <= n; i++) {
          dp[i][0][0] = dp[i - 1][1][1];
          if (vec[i - 1] > vec[i])dp[i][0][0] = min(dp[i][0][0]  , dp[i - 1][1][0]);

          dp[i][0][1] = min(dp[i - 1][1][0] , dp[i - 1][1][1]) + 1;

          dp[i][1][0] = dp[i - 1][0][1];
          if (vec[i - 1] < vec[i])dp[i][1][0] = min(dp[i][1][0] , dp[i - 1][0][0]);

          dp[i][1][1] = min(dp[i - 1][0][0] , dp[i - 1][0][1]) + 1;
    }
      ans = min({dp[n][0][0] , dp[n][0][1] , dp[n][1][0] , dp[n][1][1]});
      cout << ans;
   /*   ll real_ans;
      out >> real_ans;
      cout << real_ans << ' ' << ans << endl;
      if (real_ans != ans) {
           cout << n << endl;
           for (int i = 1; i <= n; i++) cout << vec[i] << ' ';
           cout << endl;
           cout << ans << ' ' << real_ans;
           return 0;
      }
      in.close();
      out.close();
    } */
}
/*

*/