#include<iostream>
#include<string>
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
int main(void){
	double a;
	double u=0,d=10000000;
	while(cin>>a){
        u=max(u,a);
        d=min(d,a);


	}
	u-=d;
	printf("%.1lf\n",u);


	return 0;
}