#include <stdio.h>
int a[10];
int main()
{
int cnt = 2;
for(int i = 0; ; i+=cnt++){
cnt = cnt >= 10? cnt%10:cnt;
// printf("i = %d cnt = %d\n",i%10+1,cnt);
if(!a[i%10]){
a[i%10] = cnt;
}
else if(a[i%10] == cnt)
break;
}
for(int i = 0; i < 10; i++)
if(!a[i])
printf("可能在第%d洞\n",i+1);
//system("pause");
return 0;
}