import java.io.*;

public class Fibonacci {

  public static int fib(int n) {
    if(n<=2) {
      return 1;
    } else {
      int n1=1;
      int n2=1;
      int nc=0;
      for(int i=2;i<=n;i++) {
       nc = n1+n2;
       n2 = n1;
       n1 = nc;
      }
      return nc;
    }
  }

  public static void main(String argv[]) throws Exception {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    System.out.print("Enter a number: ");
    String s = br.readLine();
    int n = Integer.parseInt(s);
    int fibNum = fib(n);
    System.out.println("The nth fibonacci number is: "+fibNum);
  }
}