Buggy python submission (verdict: Runtime Error):
a ,b= map(int,input().split())
aaa = [list(map(int,input().split())) for i in range(b*2)]
 
s = {i+1 for i in range(a)}

for i in range(1,a+1,2):
    for k in aaa[i]:
        for j in k:
            s.discard(j)
print(len(s))

Fixed submission:
a,b = map(int,input().split())
aaa = [list(map(int,input().split())) for i in range(b*2)]

c = set()
e = set()
for i in range(1,len(aaa),2):
  for k in aaa[i]:
     c.add(k)
    
print(a - len(c))

Buggy python submission (verdict: Runtime Error):
a ,b= map(int,input().split())
aaa = [list(map(int,input().split())) for i in range(b*2)]
 
s = {i+1 for i in range(a)}


if(a == 0):
    print(0)
elif(b == 0):
    print(len(aaa))
else:
    for i in range(1,a+1,2):
        for k in aaa[i]:
            s.discard(k)
    print(len(s))

Fixed submission:
a,b = map(int,input().split())
aaa = [list(map(int,input().split())) for i in range(b*2)]

c = set()
e = set()
for i in range(1,len(aaa),2):
  for k in aaa[i]:
     c.add(k)
    
print(a - len(c))

Buggy python submission (verdict: Runtime Error):
a ,b= map(int,input().split())
aaa = [list(map(int,input().split())) for i in range(b*2)]
 
s = {i + 1 for i in range(0,a)}

for i in range(1,a+1,2):
    for k in aaa[i]:
        s.discard(k)

print(len(s))

Fixed submission:
a,b = map(int,input().split())
aaa = [list(map(int,input().split())) for i in range(b*2)]

c = set()
e = set()
for i in range(1,len(aaa),2):
  for k in aaa[i]:
     c.add(k)
    
print(a - len(c))

Buggy python submission (verdict: Runtime Error):
a ,b= map(int,input().split())
aaa = [list(map(int,input().split())) for i in range(b*2)]
 
s = {i for i in range(1,a+1)}

if a == 0:
    print(0)
    exit

if b == 0:
    print(len(aaa))
    exit
    

for i in range(1,a+1,2):
    for k in aaa[i]:
        s.discard(k)
 
print(len(s))

Fixed submission:
a,b = map(int,input().split())
aaa = [list(map(int,input().split())) for i in range(b*2)]

c = set()
e = set()
for i in range(1,len(aaa),2):
  for k in aaa[i]:
     c.add(k)
    
print(a - len(c))

Buggy python submission (verdict: Runtime Error):
import sys
a ,b= map(int,input().split())
aaa = [list(map(int,input().split())) for i in range(b*2)]
 
s = {i for i in range(1,a+1)}

if a == 0:
    print(0)
    sys.exit

if b == 0:
    print(len(aaa))
    sys.exit
    

for i in range(1,a+1,2):
    for k in aaa[i]:
        s.discard(k)
 
print(len(s))

Fixed submission:
a,b = map(int,input().split())
aaa = [list(map(int,input().split())) for i in range(b*2)]

c = set()
e = set()
for i in range(1,len(aaa),2):
  for k in aaa[i]:
     c.add(k)
    
print(a - len(c))

Buggy python submission (verdict: Runtime Error):
import sys
a ,b= map(int,input().split())
aaa = [list(map(int,input().split())) for i in range(b*2)]
 
s = {i for i in range(1,a+1)}

if a == 0:
    print(0)
    sys.exit

if b == 0:
    [print(i) for i in aaa]
    sys.exit
    

for i in range(1,a+1,2):
    for k in aaa[i]:
        s.discard(k)
 
print(len(s))

Fixed submission:
a,b = map(int,input().split())
aaa = [list(map(int,input().split())) for i in range(b*2)]

c = set()
e = set()
for i in range(1,len(aaa),2):
  for k in aaa[i]:
     c.add(k)
    
print(a - len(c))

Buggy python submission (verdict: Runtime Error):
a ,b= map(int,input().split())
aaa = [list(map(int,input().split())) for i in range(b*2)]

s = {i for i in range(1,a+1)}

for i in range(1,a+1,2):
    for k in aaa[i]:
        s.discard(k)

print(len(s))

Fixed submission:
a,b = map(int,input().split())
aaa = [list(map(int,input().split())) for i in range(b*2)]

c = set()
e = set()
for i in range(1,len(aaa),2):
  for k in aaa[i]:
     c.add(k)
    
print(a - len(c))