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#include <unistd.h>
#include <string>
#include <vector>
#include <map>
#include <deque>
#include <iostream>
#include <algorithm>

using namespace std;
#define REP(i,n) for(int _n=(n), i=0;i<_n;++i)
#define FOR(i,a,b) for(int i=(a),_b=(b);i<=_b;++i)
#define FORD(i,a,b) for(int i=(a),_b=(b);i>=_b;--i)
#define TRACE(x) cerr << "TRACE(" #x ")" << endl;
#define DEBUG(x) cerr << #x << " = " << (x) << endl;
typedef long long LL;
typedef unsigned long long ULL;
using VINT = vector<int>;
using VLL = vector<LL>;
using VULL = vector<ULL>;

// parser by tczajka

class Input {
 public:
  Input() { bufpos = bufend = buffer; eof = false; }
  bool Eof() { return eof; }
  char Peek() { if(bufpos == bufend) Grab(); return *bufpos; }
  unsigned char UPeek() { return static_cast<unsigned char>(Peek()); }
  void SkipWS();
  template<class T> T Get();
  void operator()() {}
  template<class Arg, class... Args> void operator()(Arg &arg, Args &... args) {
    arg = Get<Arg>();
    operator()(args...);
  }
 private:
  static const int BUFSIZE = 1<<16;
  char buffer[BUFSIZE];
  char *bufpos;
  char *bufend;
  bool eof;
  void Grab();
};

void Input::Grab() {
  if(eof) return;
  bufpos = buffer;
  bufend = buffer + read(0, buffer, BUFSIZE);
  if(bufend==bufpos) { eof=true; *bufpos=0; }
}

template<> inline char Input::Get<char>() {
  char res = Peek();
  ++bufpos;
  return res;
}

void Input::SkipWS() {
  while(isspace(UPeek())) Get<char>();
}

template<> unsigned Input::Get<unsigned>() {
  SkipWS();
  unsigned x = 0;
  while(isdigit(UPeek())) {
    x = 10u * x + (Get<char>()-'0');
  }
  return x;
}

template<> int Input::Get<int>() {
  SkipWS();
  bool neg = false;
  if(Peek()=='-') { neg=true; Get<char>(); }
  unsigned x = Get<unsigned>();
  if (neg) x = -x;
  return static_cast<int>(x);
}

template<> ULL Input::Get<ULL>() {
  SkipWS();
  ULL x = 0;
  while(isdigit(UPeek())) {
    x = 10ULL * x + (Get<char>()-'0');
  }
  return x;
}

template<> LL Input::Get<LL>() {
  SkipWS();
  bool neg = false;
  if(Peek()=='-') { neg=true; Get<char>(); }
  ULL x = Get<ULL>();
  if (neg) x = -x;
  return static_cast<LL>(x);
}

template<> string Input::Get<string>() {
  SkipWS();
  string s;
  while(!Eof() && !isspace(UPeek())) s += Get<char>();
  return s;
}

struct Node {
  vector<int> next_nodes;
};

Input IN;

int countMoves(VINT dzwieki, bool goUp) {
  int ret = 0;
  int current = dzwieki[0];
  int next;
  for(int i = 1; i < dzwieki.size(); i++) {
    next = dzwieki[i];
    if (goUp && next <= current) {
      next = 1000001;
      ret++;
    }
    if (!goUp && next >= current) {
      next = -1000001;
      ret++;
    }
    current = next;
    goUp = !goUp;
  }
  return ret;
}

int main() {
  std::ios_base::sync_with_stdio(false);
  int n, a;
  std::cin >> n;
  std::vector<int> dzwieki;
  dzwieki.reserve(n);
  REP(i, n) {
    std::cin >> a;
    dzwieki.push_back(a);
  }
  auto ret1 = countMoves(dzwieki, true);
  auto ret2 = countMoves(dzwieki, false);
  std::cout << std::min(ret1, ret2) << std::endl;
  return 0;
}