计蒜客- 简单斐波那契

import java.util.Scanner;
public class Main {

/**
* @param args
*/
public static void main(String[] args) {

int a,t=0;

Scanner input = new Scanner(System.in);
a = input.nextInt();
int[] arr = new int[a];

if(a==0)
{
System.out.println(0);
System.exit(0);

}
if(a<=2)
{
System.out.println(1);
System.exit(0);

}
if(a>=3){
arr[0]=0;
arr[1]=1;
}
for(int i=2;i<a;i++)
{
arr[i] = arr[i-1]+arr[i-2];
t=arr[i]+arr[i-1];
}
System.out.println(t);
}

}