Buggy python submission (verdict: Runtime Error):
#coding: utf-8

class Queue:
    class Cell:
        def __init__(self,data,link=None):
            self.data=data
            self.link=link
    
    def __init__(self):
        self.size=0
        self.front=None
        self.rear=None

    def enqueue(self,x):
        if self.size==0:
            self.front = self.rear = Queue.Cell(x)
        else:
            new_cell = Queue.Cell(x)
            self.rear.link=new_cell
            self.rear=new_cell
        self.size +=1

    def dequeue(self):
        if self.size==0:
            raise IndexError
        value=self.front.data
        self.front=self.front.link
        self.size -=1
        if self.size==0:
            self.rear=None
        return value

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

def generator(n1, n2, step=1):
    n = n1
    while n<n2:
        yield n
        n+= step

n, q = map(int, raw_input().split())
 
que = queue()
for i in generator(0,n):
    name, time = raw_input().split()
    que.enqueue([name, int(time)])

stime = 0
while not que.isEmpty:
    job = que.dequeue()
    tmp=min(q,job[1])
    stime += tmp
    job[1] -= tmp
    if job[1]==0:
        print job[0], stime
    else:
        que.que.enqueue(job)

Fixed submission:
import sys

class Queue:
    class Cell:
        def __init__(self, x, y = None):
            self.data = x
            self.next = y

    def __init__(self):
        self.size = 0
        self.rear = None

    def enqueue(self, x):
        if self.size == 0:
            self.rear = Queue.Cell(x)
            self.rear.next = self.rear
        else:
            new_cell = Queue.Cell(x, self.rear.next)
            self.rear.next = new_cell
            self.rear = new_cell
        self.size += 1

    def dequeue(self):
        if self.size == 0: raise IndexError
        front = self.rear.next
        self.rear.next = front.next
        self.size -= 1
        if self.size == 0: self.rear = None
        return front.data

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

def generator(n1, n2, step=1):
    n = n1
    while n<n2:
        yield n
        n+= step

n, q = map(int, raw_input().split())
TASK=[]
A = Queue()
for i in generator(0,n):
    name, time = raw_input().split()
    TASK.append([name, int(time)])
    A.enqueue(i)

stime = 0
while not A.isEmpty():
    p = A.dequeue()
    if q>= TASK[p][1]:
        stime += TASK[p][1]
        print TASK[p][0], stime
    else:
        stime += q
        TASK[p][1] -= q
        A.enqueue(p)

Buggy python submission (verdict: Runtime Error):
#coding: utf-8
import sys

class Queue:
    class Cell:
        def __init__(self, x, y = None):
            self.data = x
            self.next = y

    def __init__(self):
        self.size = 0
        self.rear = None

    def enqueue(self, x):
        if self.size == 0:
            self.rear = Queue.Cell(x)
            self.rear.next = self.rear
        else:
            new_cell = Queue.Cell(x, self.rear.next)
            self.rear.next = new_cell
            self.rear = new_cell
        self.size += 1

    def dequeue(self):
        if self.size == 0: raise IndexError
        front = self.rear.next
        self.rear.next = front.next
        self.size -= 1
        if self.size == 0: self.rear = None
        return front.data

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

def generator(n1, n2, step=1):
    n = n1
    while n<n2:
        yield n
        n+= step

n, q = map(int, raw_input().split())
 
A = Queue()
for i in generator(0,n):
    name, time = raw_input().split()
    A.enqueue([name, int(time)])

stime = 0
while not A.isEmpty():
    job = A.dequeue()
    if q>=job[1]:
        stime += job[1]
        print job[0], stime
    else:
        stime += q
        job[1] -= tmp
        A.enqueue(job)

Fixed submission:
import sys

class Queue:
    class Cell:
        def __init__(self, x, y = None):
            self.data = x
            self.next = y

    def __init__(self):
        self.size = 0
        self.rear = None

    def enqueue(self, x):
        if self.size == 0:
            self.rear = Queue.Cell(x)
            self.rear.next = self.rear
        else:
            new_cell = Queue.Cell(x, self.rear.next)
            self.rear.next = new_cell
            self.rear = new_cell
        self.size += 1

    def dequeue(self):
        if self.size == 0: raise IndexError
        front = self.rear.next
        self.rear.next = front.next
        self.size -= 1
        if self.size == 0: self.rear = None
        return front.data

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

def generator(n1, n2, step=1):
    n = n1
    while n<n2:
        yield n
        n+= step

n, q = map(int, raw_input().split())
TASK=[]
A = Queue()
for i in generator(0,n):
    name, time = raw_input().split()
    TASK.append([name, int(time)])
    A.enqueue(i)

stime = 0
while not A.isEmpty():
    p = A.dequeue()
    if q>= TASK[p][1]:
        stime += TASK[p][1]
        print TASK[p][0], stime
    else:
        stime += q
        TASK[p][1] -= q
        A.enqueue(p)