//FtoC.cpp
//author: 4003
//description: Temperature Convertion

#include <iostream>
using namespace std;

int main()
{
	//declare variables
	double tempF;
	double tempC;

	//initialize variables
	cin >> tempF;
	
	//compute temp celsius
	tempC = (tempF - 32) * (5.0/9);

	//output 
	cout << tempC;

	return 0;

}