hdu-1021 Fibonacci Again

#include<cstdio>
#define N 1000000
int f
;
int main()
{
f[0]=7;
f[1]=11;
for(int i=3;i<N;i++)
f[i]=(f[i-1]+f[i-2])%3;
int n;
while(scanf("%d",&n)!=EOF)
{
if(f
%3==0) printf("yes\n");
else printf("no\n");
}
return 0;
}