GSM module SIM 800 A

#include <SoftwareSerial.h>

SoftwareSerial sim900(10,11);

void setup()
{
  Serial.begin(19200);
  sim900.begin(19200);
  delay(2000);
  Serial.print(" sim800 ready...");
  delay(1000);
}

void loop()
{
sim900.println("AT+CMGF=1");
delay(500);
sim900.println("AT+CMGS="+91xxxxxxxxxx"");
delay(500);
sim900.println("hello");
delay(100);
Serial.println(sim900.read()); //this line is throwing the above message (-1, continuously) on the serial monitor
sim900.println((char)26);
delay(1000);
}