arduino mega 2560 not working properly

Development Tools IDE 1.x
6

if change code this output comes after 10 times correct it starts show only h again and again.
:confused:

ÿhello
hello
hello
hello
hello
hello
hello
hello
hello
hello
helhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh

void setup()
{
  Serial.begin(9600);
  Serial1.begin(9600);
}
void loop()
  {
  Serial1.println("hello"); 
  Serial.write(Serial1.read());
  delay(1000);
  }