Buggy python submission (verdict: Runtime Error):
import java.util.Scanner;

public class Main {

	static class Node<E> {
		public E value;
		public Node<E> next;		
		public Node(E value) {
			this.value = value;
			this.next = null;
		}
	}

	static class SimpleQueue<E> {
		
		private Node<E> head;
		private Node<E> tail;
		int size;
		
		public SimpleQueue() {
			size = 0;
			head = null;
			tail = null;
		}
		
		public int getSize() {
			return size;
		}
		
		public boolean isEmpty() {
			return size == 0;
		}
		
		public void enqueue(E element) {
			Node<E> node = new Node<E>(element);
			if (head == null && tail == null) {
				head = tail = node;
			} else {
				tail.next = node;
				tail = node;
			}
			size++;
		}
		
		public E dequeue() {			
			if (isEmpty()) {
				return null;
			}
			E element = head.value;
			head = head.next;
			if (head == null) {
				tail = null;
			}
			size--;
			return element;			
		}
		
		public String toString() {
			StringBuilder sb = new StringBuilder();
			sb.append("[");
			Node<E> current = head;
			while (current != null) {
				sb.append(current.value);
				current = current.next;
				if (current != null) {
					sb.append(", ");
				}
			}			
			sb.append("](");
			if (tail != null) {
				sb.append(tail.value);
			}
			sb.append(")");
			return sb.toString();
		}		
	}
	
	static class Process {		
		public String name;
		public int time;		
		public Process(String name, int time) {
			this.name = name;
			this.time = time;
		}		
	}
	
	public static void main(String[] args) {
		
		Scanner sc = new Scanner(System.in);
		
		int n = sc.nextInt();
		int q = sc.nextInt();
		
		SimpleQueue<Process> queue = new SimpleQueue<Process>();
		for (int i = 0; i < n; i++) {
			String name = sc.next();
			int time = sc.nextInt();
			queue.enqueue(new Process(name, time));
		}
		sc.close();

		int total = 0;
		while (!queue.isEmpty()) {
			
			Process process = queue.dequeue();
			if (process.time > q) {
				process.time = process.time - q;
				total += q;
				queue.enqueue(process);
			} else {
				total += process.time;
				System.out.println(process.name + " " + total);
			}			
		}
	}
}




Fixed submission:

class Node:
	def __init__(self, value):
		self.value = value
		self.next = None

class SimpleQueue:
	def __init__(self):
		self.size = 0
		self.head = None
		self.tail = None
		return

	def enqueue(self, value):
		node = Node(value)
		if self.head == None:
			self.head = node
			self.tail = node
		else:
			self.tail.next = node
			self.tail = node
		self.size += 1

	def dequeue(self):
		if self.is_empty() == True:
			return None
		node = self.head
		self.head = self.head.next
		if self.head == None:
			self.tail = None
		self.size -= 1
		return node.value

	def peek(self):
		if self.is_empty() == True:
			return None
		return self.head.value

	def get_size(self):
		return self.size

	def is_empty(self):
		return self.size == 0

	def __str__(self):
		str_ = '['
		current = self.head
		while current != None:
			str_ += str(current.value)
			current = current.next
			if current != None:
				str_ += ', '
		str_ += ']['
		if self.tail != None:
			str_ += str(self.tail.value)
		str_ += ']'
		return str_

class Process:
	def __init__(self, name, time):
		self.name = name
		self.time = int(time)

	def set_time(self, time):
		self.time = time

n, q = map(int, input().split())
myqueue = SimpleQueue()
for i in range(n):
	name, time = map(str, input().split())
	myqueue.enqueue(Process(name, time))

time_elapsed = 0
while myqueue.is_empty() != True:
	process = myqueue.dequeue()
	time = process.time
	if time > q:
		process.set_time(time - q)
		time_elapsed += q
		myqueue.enqueue(process)
	else:
		time_elapsed += time
		print(process.name + ' ' + str(time_elapsed))