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

  
int main(){
	double hmax, hmin;
	double h;

	bool f = true;

	while(cin >> h){
		if(f){
			hmax = h;
			hmin = h;
			f = false;
		}else{
			hmax = max(hmax, h);
			hmin = min(hmin, h);
		}
	}

	cout << hmax-hmin << endl;

	return 0;
}