void setup()
{
 int sum = 0;
 Serial.begin(9600);
 // count up to 25 in 5s
 while (sum < 25 )
 { 
   sum = sum + 5;
   Serial.print("sum = " );
   Serial.println(sum);
   delay(500);            // 500ms delay
  }
}
 void loop() {  }