#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;
int main(){
	double h;
	vector<double> high;
	while(cin>>h){
		high.push_back(h);
	}
	double a=high[0],b=high[0];
	for(int i=0;i<high.size();i++){
		a=max(a,high[i]);
		b=min(b,high[i]);
	}
	cout<<a-b<<endl;
	return 0;
}