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#include <cstdio>

int tab[50001],i,n,sum,prev,flag,nextsum;

int getResult(){
	int ress=0;
	for(i=0;i<n;i++){
		if(flag){
			if(prev<tab[i]){
				prev=tab[i];
			}
			else{
				prev=10000001;
				ress++;
			}
		}
		else{
			if(prev>tab[i]){
				prev=tab[i];
			}
			else{
				prev=-10000001;
				ress++;
			}
		}
		flag=!flag;
	}
	//printf("%d\n",ress);
	return ress;
}

int main(){
	scanf("%d",&n);
	for(i=0;i<n;i++)scanf("%d",&tab[i]);
	
	sum=n;
	
	prev=-10000001;
	flag=true;
	nextsum = getResult();
	if(nextsum<sum)sum=nextsum;
	
	prev=10000001;
	flag=false;
	nextsum = getResult();
	if(nextsum<sum)sum=nextsum;
	
	printf("%d\n",sum);
	return 0;
}