#include <avr/io.h>    		

int main(void) 
{	
	DDRB = DDRB & ~(1<<7);		

	while (1)
	{
		if(PINB & (1<<7))
			DDRB = DDRB & ~(1<<4);	
		else
			DDRB = DDRB | (1<<4);
	}
	
	return 0;
}