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

int main()
{
DDRB|=(1<<PB5);//HIGH THE PIN FOR OUTPUT
DDRB&=~(1<<PB4);//LOW THE PIN FOR INPUT
PORTB|=(1<<PB4);
/*
HIGH THE PIN FOR PULLUP.**WE CANNOT READ DATA FROM PORT REGISTER 
PORT REGISTER IT ONLY GOR PULL-UP AND PULL-DOWN
PIN REGISTER USED FOR READ THE DATA
*/
while(1)
{

if(PINB & (1<<PB4))//WE JUST OR THE REGISTER WITH PB4(NUMARICALY 4)
PORTB|=(1<<PB5);

else
PORTB&=~(1<<PB5);

}
  return 0;
}