#include<iostream>
#include<cmath>
using namespace std;
int main(void) {
    double x;
    cin>>x;
    double hig=x, low=x;
    while(cin >> x){
        if(hig<x)hig=x;
        if(low>x)low=x;
    }
    cout << hig-low << endl;
    return 0;
}
