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

int main()
{
  double ans;
  vector<double> a;

  while ( scanf("%lf",&ans) != EOF){
    a.push_back( ans );
  }


  double c = a[0];
  double d = a[0];
  for(int i=0; i<a.size(); i++){
    c=max(c, a[i]);
    d=min(c, a[i]);
  }

  printf("%f\n",c-d);
}