#include <iostream>
using namespace std;

/** Problem0046 : Differential **/

int main()
{
	double max, min, input;
	cin >> max; min = max;
	
	while (cin >> input) {
		if (max < input)
			max = input;
		else if (min > input)
			min = input;
	}
	
	cout << max - min << endl;
	return 0;
}