#include<string>
#include<vector>
#include<iostream>
#include<sstream>
#include<cstdio>
#include<cstdlib>
#include<functional>
#include<algorithm>
#include<stack>
#include<queue>
#include<deque>
#include<set>
#include<map>
#include<utility>
#include<cmath>
#include<ctime>
#include<complex>

using namespace std;

#define REP(i,s,e) for(int i=int(s);i<=int(e);i++)
#define rep(i,n) for(int i=0;i<int(n);i++)

int main(){

	double h;
	double h1=10000.0;
	double h2=0.0;

	while(true){

	cin >> h;
	if(h==0.0) break;

	if(h<=h1) h1=h;
	if(h>=h2) h2=h;

	}

	cout << h2-h1 << endl;

	return 0;
}