#include<iostream>
#include<algorithm>
#include<vector>

using namespace std;

vector<double> M;
double h;

int main(){
  
  while(1){
    cin >>h;
    M.push_back(h);
    sort(M.begin(),M.end());
    if(cin.eof()){break;}
  }
      printf("%.1f\n",M[M.size()-1]-M[0]);
  return 0;
}