#include<cstdio>
#include<iostream>

#define INF 100000000000.0
using namespace std;

int main(void){

	double high,min=INF,max=-1*INF;

	while(scanf("%lf",&high)!=EOF){
		if(max<high) max=high;
		if(min>high) min=high;
	}

	printf("%.1f\n",max-min);


	return 0;
}