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#include <cstdio>
#include <vector>
#include <algorithm>
#include <string>
#include <cstring>
#include <sstream>
#include <iostream>
#include <map>
#include <cmath>
#include <set>
#include <queue>
#include <numeric>
#include <ctime>

using namespace std;
typedef long long LL;
#define INF 1000000000
#define SZ(v) ((int)(v).size())
#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define FORE(i,a,b) for(int i=(a);i<=(b);i++)
#define FS first
#define SD second
#define MP make_pair
#define ZERO(t) memset(t, 0, sizeof(t))
#define MINUS(t) memset(t, -1, sizeof(t))
#define MOD 1000000007
#define MIN(_a,_b) ((_a)<(_b)?(_a):(_b))
#define MAX(_a,_b) ((_a)>(_b)?(_a):(_b))

vector<int> numbers;

int go(int start) {
  int low = 1, high = 1, org = 0;
  
  FOR(i,1,SZ(numbers)) {
    int down = (i % 2 == start);
    int low2 = INF, high2 = INF, org2 = INF;
    if (down) {
      low2 = MIN(high + 1, org + 1);
      org2 = high;
      if (numbers[i] < numbers[i - 1]) org2 = MIN(org2, org);
    }
    else {
      high2 = MIN(low + 1, org + 1);
      org2 = low;
      if (numbers[i] > numbers[i - 1]) org2 = MIN(org2, org);
    }
    low = low2;
    high = high2;
    org = org2;
  }

  return MIN(MIN(low, high), org);
  
}

int main() {
  int n; scanf("%d", &n);
  
  FOR(i,0,n) {
    int a; scanf("%d", &a);
    numbers.push_back(a);
  }
  
  printf("%d\n", MIN(go(0), go(1)));
}