#include <stdio.h>

int main(){
	int num = 0;
	int info[num];
	
	int *p = info;
	for(int i = 0;i < num;i++){
		scanf("%d",&p[i]);
	}
	
	int count = 0;
	for(int i = 0;i < num;i++){
		if (p[i] != p[i+1] && p[i] != p[i-1]){
			count++;
		}	
	}
	printf("%d",count);
}