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

int main(void){
  double mountain,max=0.0,min=100000.0;

  while( scanf("%lf" ,&mountain ) != EOF ){
    if( max < mountain ) max = mountain;
    if( min > mountain ) min = mountain;
  }
  cout << max - min << endl;
  return 0;
}