int f(int year) //year年的1月1日是周几?(year>=1998)
{
	if(year==1998)
	{
		return 4;
	}
	else //1998.1.1~year.1.1
	{
		int tim=4;
		for(int i=1998;i<year;i++)
		{
			if(leap(i))
			{
				tim+=366;
				tim%=7;
				tim++;
			}
			else
			{
				tim+=365;
				tim%=7;
				tim++;
			}
		}
		return tim;
	}
}