#include<iostream>
#include<string>
#include<cmath>
#include<algorithm>
using namespace std;

int main(){
  double min=10000000,max=0;
  double h;
  
  while(cin>>h){
    if(max<h)max=h;
    if(min>h)min=h;
  }
  cout<<max-min<<endl;



  return 0;
}