/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;
import java.math.*;
 
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		BufferedReader k = new BufferedReader(new InputStreamReader(System.in));
		PrintWriter out = new PrintWriter(new OutputStreamWriter(System.out));
		BigInteger []arr = new BigInteger[1000];
		arr[0]=BigInteger.ZERO;arr[1]=BigInteger.ONE;
		for(int i=2;i<1000;i++){
			arr[i] = arr[i-1].add(arr[i-2]);
		}
		String s;
		while((s=k.readLine())!=null){
			out.println(arr[Integer.parseInt(s)]);
		}
		out.close();
		k.close();
		// your code goes here
	}
}

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

MQoyCjMKNAo1

1
2
3
4
5