#include
using namespace std;
int F(int n)
{
if(n<=0)
return 0;
if(n==1)
return 1;
int* ans = new int[n+1];
ans[0] = 0;
ans[1] = 1;
for(int i=2; i<=n; i++)
ans[i] = ans[i-1] + ans[i-2];
int tmp = ans[n];
delete[] ans;
return tmp;
}