#include<bits/stdc++.h> 
using namespace std;
int main(){
    int n;
	float x,g,s;
	cin>>n;
	g=n%10;
	s=n/10%10;
	x=s/g/1.0;
	printf("%.1f",x); 
	 
} 
/**************************************************************
	Problem: 1607
	User: yangjunwen
	Language: C++
	Result: Accepted
	Time:6 ms
	Memory:2072 kb
****************************************************************/