Date to day converter

 

// created and thought by Kartik Sharma
import java.util.*;
public class HelloWorld {
    public static void main(String[] args) {
    int n=0;
    while(n<1){
        Scanner sc=new Scanner(System.in);
        int y1=2000;
        int u=0;
        //year section
        System.out.print("enter year = ");
        int y2=sc.nextInt();
        int x=(y2-y1)+((y2-y1)/4);
        //month section
System.out.print("enter month = ");
        int m2=sc.nextInt();
     if(m2==1){                      u=u+0;}
else if(m2==2){
            u=u+3; }
else if(m2==3){
            u=u+3;}
else if(m2==4){
            u=u+6 ;}
else if(m2==5){
            u=u+ 8;}
else if(m2==6){
            u=u+11 ;}
else if(m2==7){
            u=u+13 ;}
else if(m2==8){
            u=u+ 16;}
else if(m2==9){
            u=u+19 ;}
else if(m2==10){
            u=u+ 21;}
else if(m2==11){
            u=u+ 24;}
else if(m2==12){
            u=u+ 26;}
   else{
       System.out.print("month not exist");
       break; }
       //day section
       System.out.print("enter date = ");
       int d2=sc.nextInt();
       if((m2==1||m2==3||m2==5||m2==7||m2==8||m2==10||m2==12)&&d2>31){
       System.out.println("date not exist");
       break; }
       else if((m2==2||m2==4||m2==6||m2==9||m2==11)&&(d2>30)){
       System.out.println("date not exist");
       break; }
       else if(((y2%4)==0&&m2==2)&&d2>29){
       System.out.println("date not exist");}
       else if(((y2%4)>0&&m2==2)&&d2>28){
       System.out.println("date not exist");}
       else{
       d2=d2+0;}
       //calculation section
       int c=(x+u+d2+7);
       int r=c%7;
       if((y2%4)==0&&m2==1||m2==2||m2==3){
           r--;
       }
       //output section
     if(r==0){
System.out.print("SATURDAY ");}
else if(r==1){
System.out.print("SUNDAY ");}
else if(r==2){
System.out.print(" MONDAY");}
else if(r==3){
System.out.print(" TUESDAY");}
else if(r==4){
System.out.print(" WEDNESDAY");}
else if(r==5){
System.out.print(" THURSDAY");}
else{
System.out.print(" FRIDAY");}
System.out.println();

       }
    }
    }