#include <iostream>
#include <stdio.h>
#include <algorithm>
using namespace std;

int main(void)
{
	double mt, maxi = -1, mini = 1000001;

	while (cin >> mt)
	{
		mini = min(mini, mt); maxi = max(maxi, mt);
	}
	printf("%.2f\n",maxi-mini);
	return 0;
}
