import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.InputMismatchException;
import java.io.OutputStream;
import java.util.StringTokenizer;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.HashMap;
import java.util.Map;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        Task solver = new Task();
        solver.solve(1, in, out);
        out.close();
    }

    static class Task {
        public void solve(int testNumber, InputReader in, PrintWriter out) {
            String D = "0.1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980818283848586878889909192939495969798991";
            int N = in.nextInt();
            int[] ichi = new int[D.length()+1];
            int[] ni = new int[D.length()+1];
            int first = N%10;
            int second = N/10;
            int c=0;
            for(int i=D.length(); i>=3; i--){
                ichi[i]=(first*(D.charAt(i-1)-'0')+c)%10;
                c=(first*(D.charAt(i-1)-'0')+c)/10;
            }
            ichi[2] = c;
            c=0;
            ni[D.length()]=0;
            for(int i=D.length(); i>=3; i--){
                ni[i-1]=(second*(D.charAt(i-1)-'0')+c)%10;
                c=(second*(D.charAt(i-1)-'0')+c)/10;
            }
            ni[1] = c;
            c=0;
            int[] res = new int[D.length()+1];
            for(int i=D.length(); i>=0; i--){
                res[i] = (ichi[i]+ni[i]+c)%10;
                c=(ichi[i]+ni[i]+c)/10;
            }
            if(N==100){
                for(int i=0; i<D.length()-2; i++){
                    res[i+1] = (D.charAt(i+2)-'0');
                }
            }
            int flag=0;
            for(int i=0; i<=D.length(); i++){
                if(flag==0 && res[i]==0 && i<2) continue;
                flag=1;
                if(i==3) out.print("."); 
                out.print(res[i]);
            }

        }
    }


    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

        public long nextLong() {
            return Long.parseLong(next());
        }

    }
}