#include<iostream>
#include<algorithm>
#include<stdio.h>
using namespace std;
double in,maxm,mini;
int main(){
	cin>>maxm;
	mini=maxm;
	while(cin>>in){
		maxm=max(maxm,in);
		mini=min(mini,in);
	}
	printf("%.6f\n",maxm-mini);
	return 0;
}