#include<iostream>
#include<vector>
#include<algorithm>
#include<cstdio>
using namespace std;
int main(){
  vector<double> high;
  double d;
  while(cin >>d) high.push_back(d);
  sort(high.begin(),high.end());
  printf("%.1lf\n",high[high.size()-1]-high[0]);
  return 0;
}