#include<bits/stdc++.h>
using namespace std;
int main(){
	int n,s;
	float g,p=0;
	scanf("%d",&n);
	g=n%10;
	s=n/10%10;
	p=s/g;
	printf("%.1f",p);
	return 0;
}
/**************************************************************
	Problem: 1607
	User: xiaojingxuan
	Language: C++
	Result: Accepted
	Time:8 ms
	Memory:2076 kb
****************************************************************/