#pragma GCC optimize("Ofast")
#pragma GCC target("avx2")

char*mmap();

main(){
	char*rp=mmap(0l,7*100001,1,2,0,0ll);
	while(*rp++!=10);
	long a,b=0;
	int c=0,d=0;
	do{
		a=0;
		do{
			a=a<<8|*rp++;
		}while(*rp>=48);
		++rp;
		c+=d=!d|a==b;
		b=a;
	}while(*rp);

	char wbuf[16],*wp=wbuf+sizeof wbuf;
	while(*--wp=c%10+48,c/=10);
	write(1,wp,(wbuf+sizeof wbuf)-wp);
	_exit(0);
}