PhoneBookEntry Driver Program error

Question

My output program is skipping the second data entry, which is the first Name entry, and I can't seem to understand why. If I define n <=2 in my while-loop, then the program runs correctly. However, it should be based on the user entry and not predefined. I would greatly appreciate as to why the program is skipping the second data entry of a person's name, and leaving it blank. Thank you!

PhoneBookEntry Class:

public class PhoneBookEntry 
{
public PhoneBookEntry(String Name, String PhoneNumber) 
{
    this.Name = Name;
    this.PhoneNumber = PhoneNumber;
}

private String Name;
private String PhoneNumber;

public String getName() 
{
    return this.Name;
}

public void setName(String Name) 
{
    this.Name = Name;
}

public String getPhoneNumber() 
{
    return this.PhoneNumber;
}

public void setPhoneNumber(String PhoneNumber) 
{
    this.PhoneNumber = PhoneNumber;
}       
}

PhoneBookEntry Driver Program:

import java.util.Scanner;
import java.util.ArrayList;
public class PhoneBookDriver 
{
public static void main(String[] args) 
{


  ArrayList<PhoneBookEntry> List = new ArrayList<PhoneBookEntry>();

  String a, b;
  int n = 1;
  int NumContacts;

  Scanner scan = new Scanner(System.in);

  System.out.println("Enter The Number Of Contacts You Want To Save: ");
  NumContacts = scan.nextInt(); 

  while (n <= NumContacts)
  {
     System.out.println("Enter A Name: ");
     a = scan.nextLine();

     System.out.println("Enter Their Phone Number: ");
     b = scan.nextLine();


     List.add(new PhoneBookEntry(a, b));

     n++;  
  }

     System.out.println("Here's The Data You Entered");
     for (PhoneBookEntry entry : List) 
     { 
        System.out.printf("Name: %s\tNumber: %s\n", entry.getName(), entry.getPhoneNumber()); 
     }
}  
}  

Output:

 ----jGRASP exec: java PhoneBookDriver
Enter The Number Of Contacts You Want To Save: 
2
Enter A Name: 
Enter Their Phone Number: 
5869302958
Enter A Name: 
Bob
Enter Their Phone Number: 
7530572957
Here's The Data You Entered
Name:  Number: 5869302958
Name: Bob Number: 7530572957

 ----jGRASP: operation complete.