#include <iostream>
#include <algorithm>
#include <vector>
#include <cstdio>
using namespace std;

int main(){
	vector<float> v;
	float input;
	while(cin >> input){
		v.push_back(input);
		sort(v.begin(), v.end());
		float ans;
		vector<float>::iterator ite;
		ite = v.end();
		ans = *(ite-1) - v.at(0);
		
	}
	printf("%.1f\n", ans);
	return 0;
}