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

int main(){
	double n;
	vector<double> v;
	while( cin >> n ){
		v.push_back( n );
	}
	double a = v[0];
	double b = v[0];
	for(int i=0 ; i < v.size() ; i++ ){
		a = max( a , v[i] );
		b = min( b , v[i] );
	}
	cout << (a-b) << endl;
}