#include <stdio.h>
#include <stdlib.h>
#include <string.h>
extern int getchar_unlocked(void);
extern int putchar_unlocked(int);
#define gc(d)	(d)=getchar_unlocked()
#define	pc(d) putchar_unlocked(d)
// *********************
int main( void ) {
	int c;
	int k = 255;
	gc(c);
	do {
		if( c != k ) pc(c);
		k = c;
		gc(c);
	} while (c != EOF);
}