#include <iostream>
#include <iomanip>
using namespace std;
int main(){
	double hight,max,min;
	cin >> hight;
	max=min=hight;
	while(cin >> hight){
		if(hight>max) max=hight;
		if(hight<min) min=hight;
	};
	cout << fixed << setprecision(1);
	cout << max-min << '\n' ;
}