#include <bits/stdc++.h>
using namespace std;
int main(){
	int a,b,c;
	float d;
	cin>>c;
	a=c/10;
	b=c%10;
	d=a*1.0/b;
	printf("%.1f",d);
	return 0;
}
/**************************************************************
	Problem: 1607
	User: panyuchen
	Language: C++
	Result: Accepted
	Time:9 ms
	Memory:2072 kb
****************************************************************/