int j_rn(int y)
{
 if(y%4==0&&y%100!=0||y%400==0)
 return 1;
 else
 return 0;
}
main()
{
 int y,m,d,s=28,n,num;
 printf("\nPlease input year,month and date:");
 scanf("%d %d %d",&y,&m,&d);
 if(j_rn(y))
 s=29;
 switch(m)
 {
  case 1:n=d;break;
  case 2:n=31+d;break;
  case 3:n=31+s+d;break;
  case 4:n=31+s+31+d;break;
  case 5:n=31+s+31+30+d;break;
  case 6:n=31+s+31+30+31+d;break;
  case 7:n=31+s+31+30+31+30+d;break;
  case 8:n=31+s+31+30+31+30+31+d;break;
  case 9:n=31+s+31+30+31+30+31+31+d;break;
  case 10:n=31+s+31+30+31+30+31+31+30+d;break;
  case 11:n=31+s+31+30+31+30+31+31+30+31+d;break;
  case 12:n=31+s+31+30+31+30+31+31+30+31+30+d;
 }
 num=(y-1)+(y-1)/4-(y-1)/100+(y-1)/400+n;
 printf("%d\n",num%7);
 getch();
}