import java.util.*;
public class Main {
public static void main(String[] args) {
int n;
int a=1;
int b=1;
int c=1;
Scanner in=new Scanner(System.in);
n=in.nextInt();
for(int i=2;i<n;i++) {
c=a+b;
b=a;
a=c;
}
System.out.println©;
}
}
import java.util.*;
public class Main {
public static void main(String[] args) {
int n;
int a=1;
int b=1;
int c=1;
Scanner in=new Scanner(System.in);
n=in.nextInt();
for(int i=2;i<n;i++) {
c=a+b;
b=a;
a=c;
}
System.out.println©;
}
}