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#include <bits/stdc++.h>

using namespace std;

int n;
int tab[500005];
int dp[2][500005];
bool ch[2][500005];

int main() {
	scanf("%d", &n);
	for(int i = 0; i < n; ++i) {
		scanf("%d", tab+i);
	}
	//0 - upper
	//1 - lower
	dp[0][0] = 0;
	dp[1][0] = 0;
	if(tab[0] == tab[1]) {
		dp[0][1] = 1;
		ch[0][1] = 1;
		dp[1][1] = 1;
		ch[1][1] = 1;
	} else if(tab[0] < tab[1]) {
		dp[0][1] = 0;
		dp[1][1] = 1;
		ch[1][1] = 1;
	} else {
		dp[0][1] = 1;
		ch[0][1] = 1;
		dp[1][1] = 0;
	}
	for(int i = 2; i < n; ++i) {
		dp[0][i] = dp[1][i-1] + (ch[1][i-1] ? 0 : (tab[i-1] >= tab[i] ? 1 : 0));
		dp[1][i] = dp[0][i-1] + (ch[0][i-1] ? 0 : (tab[i-1] <= tab[i] ? 1 : 0));
		ch[0][i] = (ch[1][i-1] ? 0 : (tab[i-1] >= tab[i] ? 1 : 0));
		ch[1][i] = (ch[0][i-1] ? 0 : (tab[i-1] <= tab[i] ? 1 : 0));
	}
	/*for(int i = 0; i < n; ++i) {
		printf("%d %d %d %d %d\n", i, dp[0][i], dp[1][i], ch[0][i], ch[1][i]);
	}*/
	printf("%d\n", min(dp[0][n-1], dp[1][n-1]));

}