#include<stdio.h>

int main(void)
{
	double h,min,max;
	
	scanf("%lf",&h);
	min=max=h;
	while(scanf("%lf",&h) != EOF)
	{
		if(max<h)
			max = h;
		else if(min>h)
			min = h;
	}
	printf("%0.1f\n",max-min);
	return 0;
}