#include <iostream>
#include <limits>
#include <algorithm>
#include <iomanip>

using namespace std;

int main()
{
    double c, l = numeric_limits<double>::max(), h = numeric_limits<double>::min();
    while( cin >> c ) {
        l = min( l, c );
        h = max( h, c );
    }

    cout << setprecision( 1 ) << fixed << h - l << endl;
}