#include<iostream>
#include<vector>
#include<algorithm>
#include<cstdio>
using namespace std;

int main(){
	vector<double> yama;
	double j;
	while(cin>>j)yama.push_back(j);
	sort(yama.begin(),yama.end());
	//cout.precision(1);
	j = yama[yama.size()-1]-yama[0];
	printf("%.1f\n",j);
}