int stbuttonPin = 2;  // change to whatever you want
int tkbuttonPin = 3;
int ledPin = 13; // just using for example
boolean tkoldval = HIGH;
boolean stoldval = HIGH;

void setup()
{
     pinMode(ledPin, OUTPUT);     // LED as output
     pinMode(stbuttonPin, INPUT);    // button as input
     digitalWrite(stbuttonPin, HIGH); // turns on pull-up resistor after input
     pinMode(tkbuttonPin, INPUT);    // button as input
     digitalWrite(tkbuttonPin, HIGH); // turns on pull-up resistor after input
     Serial.begin(9600);
}

void loop()
{
tkoldval = digitalRead(tkbuttonPin);
stoldval = digitalRead(stbuttonPin);
     if( (tkoldval == HIGH) &(digitalRead(tkbuttonPin) == LOW ))   // when pin goes LOW
	   {
	    Serial.println('t');	 
            digitalWrite(ledPin, HIGH);	     // turn on LED
            delay(10);
	    }
     if( (stoldval == HIGH) & (digitalRead(stbuttonPin) == LOW ))   // when pin goes LOW
	   {
	    Serial.println('s');	 
            digitalWrite(ledPin, HIGH);	     // turn on LED
            delay(10);
	    }

    digitalWrite(ledPin, LOW);	  // well, turns led off!
    //delay(1000); //one second delay

}