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#include <stdio.h>
#define Min -10000000
#define Max 10000000

void shouldBeGreater(int a, int& prev, int& result) {
	if(prev < a) {
		prev = a;
	}
	else //>= 
	{
		prev = Max;
		result++;
	}
}

void shouldBeLower(int a, int& prev, int& result) {
	if(prev > a) {
		prev = a;
	}
	else //<=
	{
		prev = Min;
		result++;	
	}
}

int main() {
	int n=0; scanf("%d ", &n);
	int result1 = 0;
	int result2 = 0;
	int prev1 = Min; //t0 is greater (than prev, t1)
	int prev2 = Max; //t0 is lower
	for(int t=0; t < n; t++) {
		int a; scanf("%d ", &a);
		if(t % 2 == 0)
		{
			shouldBeGreater(a, prev1, result1);
			shouldBeLower(a, prev2, result2);
		}
		else{
			shouldBeLower(a, prev1, result1);
			shouldBeGreater(a, prev2, result2);
		}
	}
	printf("%d\n", result1 < result2 ? result1 : result2);
	return 0;
}