Buggy python submission (verdict: Runtime Error):
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# D-Grid and Integers

from collections import defaultdict

def ReadInput():
	return [int(i) for i in input().split(" ")]

(R, C) = ReadInput()
N = int(input())
VectorSet = set() 
Grid = defaultdict(list)
for i in range(N):
	(r, c, a) = ReadInput()
	Grid[("R", r)].append((("C", c), a))
	Grid[("C", c)].append((("R", r), a))
	VectorSet.add(('R', r))
	VectorSet.add(('C', c))

def iteration(vector):
	VectorSet.discard(vector)
	for (v, a) in Grid[vector]:
		temp = a - VectorCover[vector]
		if (v in VectorCover):
			if(temp != VectorCover[v]):
				print("No")
				print("No equal")
				exit()
		else:
			VectorCover[v] = temp
			iteration(v) 

while(len(VectorSet) != 0):
	vector = VectorSet.pop()
	VectorCover = dict() 
	VectorCover[vector] = 0
	iteration(vector)
	minR = min(a for (p, a) in VectorCover.items() if (p[0] == "R"))
	minC = min(a for (p, a) in VectorCover.items() if (p[0] == "C"))
	if (minR + minC < 0):
		print("No")
		print("min")
		exit()
		
print("Yes")

Fixed submission:
#A-Codefestival 2016
str=input()
str1=str[:4]+" "+str[4:]
print(str1)

Buggy python submission (verdict: Runtime Error):
from collections import defaultdict

def readInput():
	return [int(i) for i in input().split(" ")]

(R, C) = readInput()
N = int(input())
rowIdx = set() 
grid = defaultdict(lambda:None)
rowGrid = defaultdict(set)
for i in range(N):
	(r, c, a) = readInput()
	r -= 1
	c -= 1
	rowGrid[r].add(c)
	grid[(r, c)] = a 
	rowIdx.add(r)

pairIdx = rowIdx.copy	
for i in rowIdx:
	pairIdx.remove(i)
	for j in pairIdx:
		tempRow = rowGrid[i]
		tempPair = rowGrid[j]
		mark = 1
		for k in tempRow:
			if (grid[(j, k)] != None):
				diff = grid[(i, k)] - grid[(j, k)]
				mark = 0 
		if (mark is 1):
			continue
		for m in tempRow:
			anchor = grid[(i, m)]
			anchorP = grid[(j, m)]
			if (anchorP is None and anchor < diff):
				print('No')
				exit()
			elif (anchorP is not None and anchor - anchorP != diff):
				print('No')
				exit()
		for n in tempPair:
			anchor = grid[(j, n)]
			anchorP = grid[(i, n)]
			if (anchorP is None and anchor < -diff):
				print('No')
				exit()
print('Yes')

Fixed submission:
#A-Codefestival 2016
str=input()
str1=str[:4]+" "+str[4:]
print(str1)

Buggy python submission (verdict: Runtime Error):
#/usr/bin/env python3
# -*- coding: utf-8 -*-
# D-Grid and Integers

from collections import defaultdict

def readInput():
	return [int(i) for i in input().split(" ")]

(R, C) = readInput()
N = int(input())
rowIdx = list() 
colIdx = list()
grid = defaultdict(lambda:None)
rowGrid = defaultdict(list)
for i in range(N):
	(r, c, a) = readInput()
	r -= 1
	c -= 1
	rowGrid[r].append(c)
	grid[(r, c)] = a 
	rowIdx.append(r)

pairIdx = rowIdx.copy()	
for i in rowIdx:
	pairIdx.remove(i)
	for j in pairIdx:
		tempRow = rowGrid[i]
		tempPair = rowGrid[j]
		mark = 1
		for k in tempRow:
			if (grid[(j, k)] != None):
				diff = grid[(i, k)] - grid[(j, k)]
				mark = 0 
		if (mark  == 1):
			continue
		for m in tempRow:
			anchor = grid[(i, m)]
			anchorP = grid[(j, m)]
			if (anchorP == None and anchor < diff):
				print('No')
				exit()
			elif (anchorP != None and anchor - anchorP != diff):
				print('No')
				exit()
		for n in tempPair:
			anchor = grid[(j, n)]
			anchorP = grid[(i, n)]
			if (anchorP == None and anchor < -diff):
				print('No')
				exit()
print('Yes')

Fixed submission:
#A-Codefestival 2016
str=input()
str1=str[:4]+" "+str[4:]
print(str1)

Buggy python submission (verdict: Runtime Error):
#/usr/bin/env python3
# -*- coding: utf-8 -*-
# D-Grid and Integers

from collections import defaultdict

def readInput():
	return [int(i) for i in input().split(" ")]

(R, C) = readInput()
N = int(input())
rowIdx = list() 
colIdx = list()
grid = defaultdict(lambda:None)
rowGrid = defaultdict(list)
colGrid = defaultdict(list)
for i in range(N):
	(r, c, a) = readInput()
	r -= 1
	c -= 1
	rowGrid[r].append(c)
	colGrid[c].append(r)
	grid[(r, c)] = a 
	rowIdx.append(r)
	colIdx.append(c)

pairIdx = rowIdx.copy()	
for i in rowIdx:
	pairIdx.remove(i)
	for j in pairIdx:
		tempRow = set(rowGrid[i])
		tempPair = set(rowGrid[j])
		intersect = tempRow.intersection(tempPair)
		if (len(intersect) == 0):
			continue
		col = list(intersect)[0]
		diff = grid[(i, col)] - grid[(j, col)] 
		for m in tempRow:
			anchor = grid[(i, m)]
			anchorP = grid[(j, m)]
			if (anchorP == None and anchor < diff):
				print('No')
				exit()
			elif (anchorP != None and anchor - anchorP != diff):
				print('No')
				exit()
		for n in tempPair:
			anchor = grid[(j, n)]
			anchorP = grid[(i, n)]
			if (anchorP == None and anchor < -diff):
				print('No')
				exit()
print('Yes')

Fixed submission:
#A-Codefestival 2016
str=input()
str1=str[:4]+" "+str[4:]
print(str1)

Buggy python submission (verdict: Runtime Error):
#!/usr/bin/env python
# -*- coding: utf-8 -*-
# D-Grid and Integers

from collections import defaultdict

def ReadInput():
	return [int(i) for i in input().split(" ")]

(R, C) = ReadInput()
N = int(input())
RowIdx = set()
ColIdx = set()
Grid = defaultdict(list)
RowGrid = defaultdict(list)
ColGrid = defaultdict(list)
for i in range(N):
	(r, c, a) = ReadInput()
	RowGrid[r].append(c)
	ColGrid[c].append(r)
	Grid[(r, c)] = a
	RowIdx.add(r)
	ColIdx.add(c)	

fresh = 1
while(fresh == 1):
	fresh = 0
	for row in RowIdx:
		if (len(RowGrid[row]) == 1):
			continue
		TempRow = RowGrid[row].copy()
		TempColGrid = ColGrid.copy()
		for pointer in TempRow:
			TempCol = TempRow.copy()
			TempCol.remove(pointer)
			for pair in TempCol:
				dif = Grid[(row, pointer)] - Grid[(row, pair)]
				ObjCol = TempColGrid[pointer].copy()
				ObjCol.remove(row)
				for obj in ObjCol:
					val = Grid[(obj, pointer)]- dif 
					if (val < 0):
						print("No")
						exit()
					if ((obj, pair) in Grid):
						if (val != Grid[(obj, pair)]):
							print("No");
							exit()
					else:
						Grid[(obj, pair)] = val
						RowGrid[obj].append(pair)
						ColGrid[pair].append(obj)
						fresh = 1
print("Yes")

Fixed submission:
#A-Codefestival 2016
str=input()
str1=str[:4]+" "+str[4:]
print(str1)

Buggy python submission (verdict: Runtime Error):
#C-Next Letter
str = input()
K = int(input())
tempK = K
result = ""
for i in range(len(str)):
	changeNum = 122-ord(str[i])+1
	if (changeNum <= tempK):
		result += "a"
		tempK -= changeNum
	else:
		result += str[i]
if (tempK != 0):
	tempK %= 26
	result = result[:-1] + chr(ord(str[-1]) + tempK)
print(result)


Fixed submission:
#A-Codefestival 2016
str=input()
str1=str[:4]+" "+str[4:]
print(str1)