#include<bits/stdc++.h>
using namespace std;
int main() {
	int n;
	float i,s,g;
	cin>>n;
	g=n%10;
	s=n/10%10;
	i=s/g/1.0;
	printf("%.1f",i);
}

/**************************************************************
	Problem: 1607
	User: chenjunlin
	Language: C++
	Result: Accepted
	Time:7 ms
	Memory:2072 kb
****************************************************************/