// No.1469 programing
package main

import (
	"bufio"
	"os"
)

func main() {
	f := os.Stdin
	buf := make([]byte, 64*1024)
	wr := bufio.NewWriter(os.Stdout)
	defer wr.Flush()

	last := byte(' ')
	for {
		n, _ := f.Read(buf)
		if n <= 0 {
			break
		}

		for _, b := range buf[:n] {
			if last != b {
				wr.WriteByte(b)
			}
			last = b

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