#21738: 恩,一行
SUNGOD
(黑龍炎使．煞氣ㄟSUNGOD)
#include <stdio.h>
int main(){
int a(printf("%d\n",scanf("%d",&a)?(a+2)/3:0));
}
#include <stdio.h>
int main(){
int a(printf("%d\n",scanf("%d",&a)?(a+2)/3:0));
}