#include <iostream>
#include <algorithm>

using namespace std;

int main(void)
{
    ios::sync_with_stdio(false);
    double max = 114514810, min = -1;
    double h;
    while(cin >> h) {
        max = max(max, h);
        min = min(min, h);
    } 
    cout << max - min << endl;

    return 0;
}