package main

import (
	"bufio"
	"os"
)

func main() {
	rbuf := make([]byte, 5_000_000+2)
	wbuf := make([]byte, 5_000_000+2)

	rlen, _ := os.Stdin.Read(rbuf[:])

	last := byte(' ')

	wlen := 0
	for _, b := range rbuf[:rlen] {
		if last != b {
			wbuf[wlen] = b
			wlen++
		}
		last = b

		if b == '\n' {
			break
		}
	}

	wr := bufio.NewWriter(os.Stdout)
	wr.Write(wbuf[:wlen])
	wr.Flush()
}