#include<iostream>
using namespace std;
int main(){
    double F, C;
    cin>>F;
    C += 5 * (F - 32) / 9;
    printf("%.5lf", C);
    return 0;
}

#include <iostream>
using namespace std;
int main()
{
    double F;
    cin>>F;
    double C = 5 * (F - 32) / 9;
    printf("%.5f",C);
    return 0;
}

#include<bits/stdc++.h>
using namespace std;
long long q,w,e,r,t,y,u,i,o,p,d,f,g,h,j,k,l,z,x,c,v,b,n,m;
string s;double dd,ee;
long long a[100000],as[100000],asd[100000];
int main()
{
	cin>>dd;
	cout<<fixed<<setprecision(5)<<(dd-32)*1.000000/9*5;
    return 0;
}