#include <iostream>
#include <cstdlib>
#include <cmath>
#include <cstdio>
/* run this program using the console pauser or add your own getch, system("pause") or input loop */
using namespace std;

int main(int argc, char *argv[]) {

double i,f;
while(cin>>i)
{
f=(i-32)*5/9;
printf("%.3lf\n",f);
}

return 0;
}