//
// example (simple) of the dynamic programming principle 
// also considere as "memoization
//
public class FibDP {   
    
    private static int fib(int n){
	int[] fib = new int[n+1];
	fib[0] = 0;
	fib[1] = 1;
	for (int i=2;i<=n;i++) fib[i] = fib[i-1] + fib[i-2];
	return fib[n];
    }
	

    public static void main(String[] args) {
	int n = Integer.parseInt(args[0]);
	System.out.println(fib(n));
    }
}