#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
int main(){
  vector<double> hight;
  for(double n;cin >>n;) hight.push_back(n);
  sort(hight.begin(),hight.end());
  cout <<hight[hight.size()-1]-hight[0]<<endl;
  return 0;
}