#include<bits/stdc++.h>
using namespace std;
int main(){
    int n,a,b;
    float s;
    cin>>n;
    a=n%10;
	b=n/10;
	s=b/1.0/a;
	printf("%.1f",s);
    
    
    
    
    
	
	
}
/**************************************************************
	Problem: 1607
	User: lvrenxiang
	Language: C++
	Result: Accepted
	Time:9 ms
	Memory:2072 kb
****************************************************************/