import java.io.*;
public class BasicJava {
    
    public static void main(String[] args) throws IOException {
    	System.out.print("Enter the temp in Fahrenhiet: ");
    	double fahr,celc;
    	String str;
    	BufferedReader input = new BufferedReader (new InputStreamReader(System.in));
    	str = input.readLine();
    	fahr = Double.valueOf(str).doubleValue();  
    	System.out.println((fahr - 32) * 5 / 9 );
    	
    	//(fahr -32) * 5/9 
    }
}