#include<stdio.h>
int main(void)
{
	float n,s;
	double max;
	double min;

	max=-1;
	min=100000;

	while(scanf("%f",&n)!=EOF){
		if(n>max){
			max=n;
		}
		if(n<min){
			min=n;
		}
	}
	s=max-min;
	printf("%.1f\n",s);
	return 0;
}