#include <avr/io.h>
#include <util/delay.h>

#define F_CPU 1000000L


 main(void)
{
  DDRA = 0b10000000; //Makes LED pin 7 of PORTA as Output & Makes Button pin 3 of PORTA as Input

  while(1) //infinite loop
  {
    if(PINA & (1<< PA3) == 1) //If switch is pressed
    {
      PORTA |= (1<< PA7); //Turns ON LED
      _delay_ms(3000); //3 second delay
      PORTA &= ~(1<< PA7); //Turns OFF LED
    }
  }
}