poj 2942: 喫糖果

#include<iostream>
using namespace std;
int main()
{
	int a[25];
	a[1] = 1;
	a[2] = 2;
	int n;
	cin>>n;
	if(n==1)
		cout<<1<<endl;
	else if(n==2)
		cout<<2<<endl;
	else
	{
		for(int i=3;i<=n;i++)
			a[i] = a[i-1] + a[i-2];
		cout<<a[n]<<endl;
	}
	return 0;
}