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

int main(){
  double n,max=0,min=INT_MAX;
  while(scanf("%lf",&n)!=EOF){
    if(max<n) max=n;
    if(min>n) min=n;
  }
  printf("%f\n",max-min);
  return 0;
}