#include<bits/stdc++.h>
using namespace std;
int main(){
    int i,a,b;
    cin>>i;
    a=i%10;
    b=i/10%10;
    printf("%.1f",b*1.0/a); 
}
/**************************************************************
	Problem: 1607
	User: lijinkai
	Language: C++
	Result: Accepted
	Time:7 ms
	Memory:2072 kb
****************************************************************/