#include <stdio.h>
#include <math.h>
#include <algorithm>
 
using namespace std;
 
int main(){
    double max = -1,min = 1000001,tmp;
 
    while(scanf("%lf",&tmp)!=EOF){
        max = (max >= tmp)?max:tmp;
        min = (min <= tmp)?min:tmp;
    }
 
    printf("%.1lf\n",max-min);
 
    return 0;
}
