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#include <iostream>
#include <cstdio>
#include <string>
#include <sstream> 
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <cmath>
#include <algorithm>
#include <cstring>
#include <ctime>
#include <cassert>
using namespace std;

#define assert_range(x,a,b) assert((a) <= (x) and (x) <= (b))
using ll = long long;
const int INF = 1e9;

const int MAX_N = 5*1e4 + 10;
int a[MAX_N];
int f[MAX_N][2][3];
const int MAX_V = 1e9;
const int MIN_V = -1e9;

const int UP = 0;
const int DOWN = 1;
const int DEC = 0;
const int ORG = 1;
const int INC = 2;

int main() {
    //ios_base::sync_with_stdio(0);
    int n;
    scanf("%d", &n);
    //cin >> n;
    for (int i = 0; i < n; ++i) {
        scanf("%d", &a[i]);
        //cin >> a[i];
    }
    for (int i = 0; i < n; ++i) {
        for (int j = 0; j < 2; ++j) {
            for (int k = 0; k < 3; ++k) {
                f[i][j][k] = INF;
            }
        }
    }

    if (a[0] < a[1]) {
        f[1][UP][ORG] = 0;
        f[1][UP][INC] = 1;
        f[1][DOWN][ORG] = 1;
        f[1][DOWN][DEC] = 1;
    } else if (a[0] > a[1]) {
        f[1][UP][ORG] = 1;
        f[1][UP][INC] = 1;
        f[1][DOWN][ORG] = 0;
        f[1][DOWN][DEC] = 1;
    } else {
        f[1][UP][ORG] = 1;
        f[1][UP][INC] = 1;
        f[1][DOWN][ORG] = 1;
        f[1][DOWN][DEC] = 1;
    }

    for (int i = 2; i < n; ++i) {
        f[i][UP][INC] = min(f[i-1][DOWN][ORG], f[i-1][DOWN][DEC]) + 1;
        f[i][DOWN][DEC] = min(f[i-1][UP][ORG], f[i-1][UP][INC]) + 1;

        f[i][UP][ORG] = f[i-1][DOWN][DEC];
        if (a[i-1] < a[i]) {
            f[i][UP][ORG] = min(f[i][UP][ORG], f[i-1][DOWN][ORG]);
        }

        f[i][DOWN][ORG] = f[i-1][UP][INC];
        if (a[i-1] > a[i]) {
            f[i][DOWN][ORG] = min(f[i][DOWN][ORG], f[i-1][UP][ORG]);
        }

    }
    int res = INF;
    for (int i = 0; i < 2; ++i) {
        for (int j = 0; j < 3; ++j) {
            res = min(res, f[n-1][i][j]);
        }
    }
    printf("%d\n", res);
    //cout << res << endl;
    return 0;
}