#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: wangyiyang
	Language: C
	Result: Compile Error
****************************************************************/