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

int main(){
  float min=0;
  float max=0;
  float height=0;

  while(cin >> height){
    if(height==0){
      break;
    }

    if(min == 0){
      min = height;
    }
    else if(min > height){
      min = height;
    }

    if(max < height){
      max = height;
    }

  }

  cout << max-min << endl;

  return 0;
}