#include<iostream>
#include<string>
#include<cmath>
using namespace std; 
int main(){
  double h;
  double max=0,min=1000000;
  while (cin>>h){
    if(h>max)max=h;
    if(h<min)min=h;
  }
  cout<<max-min<<endl;  

  return 0;
}