#include<iostream>
using namespace std;
int main(){
  double a,ans;
  double tans = 0,hans = 0;
  cin >> a;
  tans = a;
  hans = a;
  while(cin>>a){
    if(tans>a) tans = a;
    if(hans<a) hans = a;
  }
  ans = hans - tans;
  cout << ans << endl;
  return 0;
}