I get this sort of thing all the time but usually several characters. I believe it is caused because the IDE closes the serial monitor before it starts uploading the sketch. As soon as the sketch has completed loading, the arduino starts to execute it and several characters are sent to the serial monitor. You then open the serial monitor, and that restarts the sketch. Your seeing a character from the first run and then the full print from the restart run.
Put a 10 second delay before your print statements, so you have time to open the serial monitor before any characters are sent and see what you get.
void setup()
{
Serial.begin(9600);
int a = 2;
int b = 49;
int c = a + b;
delay(10000);
Serial.println(c);
}
void loop()
{}