Buggy python submission (verdict: Runtime Error):
N=int(input())
A=list(map(int,input().split(" ")))
A_p = [ a for a in A if a > 0 ]
A_n = [ -1*a for a in A if a < 0 ]
A_0 = [ a for a in A if a == 0 ]

l_p = len(A_p)
l_n = len(A_n)
l_0 = len(A_0)

if l_p == 0:
    if l_n%2 == 0:
        print(sum(A_n.append(0)))
    if l_0 > 0:
        print(sum(A_n.append(0)))
    else:
        tmp_n=min(A_n)
        A_n.remove(tmp_n)
        print(sum(A_n.append(0))-tmp_n)
elif l_n == 0:
    print(sum(A_p.append(0)))

elif l_n%2 == 0:
    print(sum(A_p)+sum(A_n))
else:
    if l_0 > 0:
        print(sum(A_p)+sum(A_n))
    else:
        if min(A_n) > min(A_p):
            tmp_n=min(A_p)
            A_p.remove(tmp_n)
            print(sum(A_p.append(0))+sum(A_n)-tmp_n)    
        else:
            tmp_n=min(A_n)
            A_n.remove(tmp_n)
            print(sum(A_p)+sum(A_n.append(0))-tmp_n)

Fixed submission:
N=int(input())
A=list(map(int,input().split(" ")))
A_p = [ a for a in A if a > 0 ]
A_n = [ -1*a for a in A if a < 0 ]
A_0 = [ a for a in A if a == 0 ]

l_p = len(A_p)
l_n = len(A_n)
l_0 = len(A_0)

if l_p == 0:
    if l_n%2 == 0:
        print(sum(A_n+[0]))
    elif l_0 > 0:
        print(sum(A_n+[0]))
    else:
        tmp_n=min(A_n)
        A_n.remove(tmp_n)
        print(sum(A_n+[0])-tmp_n)
elif l_n == 0:
    print(sum(A_p+[0]))

elif l_n%2 == 0:
    print(sum(A_p)+sum(A_n))
else:
    if l_0 > 0:
        print(sum(A_p)+sum(A_n))
    else:
        if min(A_n) > min(A_p):
            tmp_n=min(A_p)
            A_p.remove(tmp_n)
            print(sum(A_p)+sum(A_n)-tmp_n)    
        else:
            tmp_n=min(A_n)
            A_n.remove(tmp_n)
            print(sum(A_p)+sum(A_n)-tmp_n)

Buggy python submission (verdict: Runtime Error):
N=int(input())
A=list(map(int,input().split(" ")))
A_p = [ a for a in A if a > 0 ]
A_n = [ -1*a for a in A if a < 0 ]
A_0 = [ a for a in A if a == 0 ]

l_p = len(A_p)
l_n = len(A_n)
l_0 = len(A_0)

if l_p == 0:
    if l_n%2 == 0:
        print(sum(A_n.append(0)))
    if l_0 > 0:
        print(sum(A_n.append(0)))
    else:
        tmp_n=min(A_n)
        A_n.remove(tmp_n)
        print(sum(A_n.append(0))-tmp_n)

elif l_n == 0:
    print(sum(A_p.append(0)))

    

if l_n%2 == 0:
    print(sum(A_p)+sum(A_n))
else:
    if l_0 > 0:
        print(sum(A_p)+sum(A_n))
    else:
        if min(A_n) > min(A_p):
            tmp_n=min(A_p)
            A_p.remove(tmp_n)
            print(sum(A_p.append(0))+sum(A_n)-tmp_n)    
        else:
            tmp_n=min(A_n)
            A_n.remove(tmp_n)
            print(sum(A_p)+sum(A_n.append(0))-tmp_n)

Fixed submission:
N=int(input())
A=list(map(int,input().split(" ")))
A_p = [ a for a in A if a > 0 ]
A_n = [ -1*a for a in A if a < 0 ]
A_0 = [ a for a in A if a == 0 ]

l_p = len(A_p)
l_n = len(A_n)
l_0 = len(A_0)

if l_p == 0:
    if l_n%2 == 0:
        print(sum(A_n+[0]))
    elif l_0 > 0:
        print(sum(A_n+[0]))
    else:
        tmp_n=min(A_n)
        A_n.remove(tmp_n)
        print(sum(A_n+[0])-tmp_n)
elif l_n == 0:
    print(sum(A_p+[0]))

elif l_n%2 == 0:
    print(sum(A_p)+sum(A_n))
else:
    if l_0 > 0:
        print(sum(A_p)+sum(A_n))
    else:
        if min(A_n) > min(A_p):
            tmp_n=min(A_p)
            A_p.remove(tmp_n)
            print(sum(A_p)+sum(A_n)-tmp_n)    
        else:
            tmp_n=min(A_n)
            A_n.remove(tmp_n)
            print(sum(A_p)+sum(A_n)-tmp_n)

Buggy python submission (verdict: Runtime Error):
N=int(input())
A=list(map(int,input().split(" ")))
A_p = [ a for a in A if a > 0 ]
A_n = [ -1*a for a in A if a < 0 ]
A_0 = [ a for a in A if a == 0 ]

l_n = len(A_n)
l_0 = len(A_0)


if l_n%2 == 0:
    print(sum(A_p)+sum(A_n))
else:
    if l_0 > 0:
        print(sum(A_p)+sum(A_n))
    else:
        if min(A_n) > min(A_p):
            tmp_n=min(A_p)
            A_p.remove(tmp_n)
            print(sum(A_p)+sum(A_n)-tmp_n)    
        else:
            tmp_n=min(A_n)
            A_n.remove(tmp_n)
            print(sum(A_p)+sum(A_n)-tmp_n)

Fixed submission:
N=int(input())
A=list(map(int,input().split(" ")))
A_p = [ a for a in A if a > 0 ]
A_n = [ -1*a for a in A if a < 0 ]
A_0 = [ a for a in A if a == 0 ]

l_p = len(A_p)
l_n = len(A_n)
l_0 = len(A_0)

if l_p == 0:
    if l_n%2 == 0:
        print(sum(A_n+[0]))
    elif l_0 > 0:
        print(sum(A_n+[0]))
    else:
        tmp_n=min(A_n)
        A_n.remove(tmp_n)
        print(sum(A_n+[0])-tmp_n)
elif l_n == 0:
    print(sum(A_p+[0]))

elif l_n%2 == 0:
    print(sum(A_p)+sum(A_n))
else:
    if l_0 > 0:
        print(sum(A_p)+sum(A_n))
    else:
        if min(A_n) > min(A_p):
            tmp_n=min(A_p)
            A_p.remove(tmp_n)
            print(sum(A_p)+sum(A_n)-tmp_n)    
        else:
            tmp_n=min(A_n)
            A_n.remove(tmp_n)
            print(sum(A_p)+sum(A_n)-tmp_n)