#include<iostream>
using namespace std;

int main() {
	float max,min;
	float input;
	
	cin >> input;
	max = input;
	min = input;
	while ( cin >> input ) {
		if ( input < min )
			min = input;
		else if ( input > max )
			max = input;
	}
	cout << max - min << endl;
}