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

int main()
{
	double hei ;

	double high = 0 ;
	double low = 0 ;

	while( cin >> hei )
	{
		if( hei > high ) high = hei ;

		if( low == 0 ) low = hei ;
		else
		{
			if( hei < low ) low = hei ;
		}
	}

	high -= low ;
	printf("%.1f\n",high) ;

	return 0 ;
}