输入年、月、日，计算星期几。计算公式为S=(y-1)*365+(y-1)div4-(y-1)div100+(y-1)div400+C-Enter year, month, day, calculating the day of the week. Calculation formula for the S = (y-1)* 365+ (Y-1) div4-(y-1) div100+ (Y-1) div400+ C