#include <iostream>

using namespace std;

int main() {
	double m, max_m=-1.0, min_m=1000000000;
	while (cin >> m) {
		if (m < min_m) min_m = m;
		else if (m > max_m) max_m = m;
	}
	double ans = max_m - min_m;
	cout << ans << endl;
}