Buggy python submission (verdict: Runtime Error):
from operator import itemgetter
from scipy.sparse import lil_matrix, csr_matrix
from scipy.sparse.csgraph import minimum_spanning_tree

def main():
    N = int(input())
    M = 10**10
    XY = [tuple(map(int, input().split())) for _ in range(N)]
    xy = [(x, i) for i, (x, _) in enumerate(XY)]
    yx = [(y, i) for i, (_, y) in enumerate(XY)]
    xy.sort()
    yx.sort()
    d = {}
    x1, i1 = xy[0]
    for x, i in xy[1:]:
        t = (i1, i) if i1 < i else (i, i1)
        d[t] = min(abs(x1 - x), d.get(t, M))
        x1, i1 = x, i
    x1, i1 = yx[0]
    for x, i in yx[1:]:
        t = (i1, i) if i1 < i else (i, i1)
        d[t] = min(abs(x1 - x), d.get(t, M))
        x1, i1 = x, i
    row = list(map(itemgetter(0), d.keys()))
    col = list(map(itemgetter(1), d.keys()))
    c = csr_matrix((list(d.values()), (row, col)), shape=(N, N))
    a = minimum_spanning_tree(c, overwrite=True)
    return a.sum(dtype=int)

print(main())


Fixed submission:
from operator import itemgetter
from scipy.sparse import lil_matrix, csr_matrix
from scipy.sparse.csgraph import minimum_spanning_tree

def main():
    N = int(input())
    M = 10**10
    XY = [tuple(map(int, input().split())) for _ in range(N)]
    xy = [(x, i) for i, (x, _) in enumerate(XY)]
    yx = [(y, i) for i, (_, y) in enumerate(XY)]
    xy.sort()
    yx.sort()
    d = {}
    x1, i1 = xy[0]
    for x, i in xy[1:]:
        t = (i1, i) if i1 < i else (i, i1)
        d[t] = min(abs(x1 - x), d.get(t, M))
        x1, i1 = x, i
    x1, i1 = yx[0]
    for x, i in yx[1:]:
        t = (i1, i) if i1 < i else (i, i1)
        d[t] = min(abs(x1 - x), d.get(t, M))
        x1, i1 = x, i
    row = list(map(itemgetter(0), d.keys()))
    col = list(map(itemgetter(1), d.keys()))
    c = csr_matrix((list(d.values()), (row, col)), shape=(N, N))
    a = minimum_spanning_tree(c, overwrite=True)
    return int(a.sum())

print(main())

Buggy python submission (verdict: Runtime Error):
from scipy.sparse import lil_matrix
from scipy.sparse.csgraph import minimum_spanning_tree

def main():
    N = int(input())
    M = 10**10
    XY = [tuple(map(int, input().split())) for _ in range(N)]
    xy = [(x, i) for i, (x, _) in enumerate(XY)]
    yx = [(y, i) for i, (_, y) in enumerate(XY)]
    xy.sort()
    yx.sort()
    d = {}
    x1, i1 = xy[0]
    for x, i in xy[1:]:
        t = (i1, i) if i1 < i else (i, i1)
        d[t] = min(abs(x1 - x), d.get(t, M))
        x1, i1 = x, i
    x1, i1 = yx[0]
    for x, i in yx[1:]:
        t = (i1, i) if i1 < i else (i, i1)
        d[t] = min(abs(x1 - x), d.get(t, M))
        x1, i1 = x, i
    l = lil_matrix((N, N), dtype=int)
    for (i, j), t in d.items():
        l[i, j] = t
    a = minimum_spanning_tree(l.tocsr())
    return a.sum(dtype=int)

print(main())


Fixed submission:
from operator import itemgetter
from scipy.sparse import lil_matrix, csr_matrix
from scipy.sparse.csgraph import minimum_spanning_tree

def main():
    N = int(input())
    M = 10**10
    XY = [tuple(map(int, input().split())) for _ in range(N)]
    xy = [(x, i) for i, (x, _) in enumerate(XY)]
    yx = [(y, i) for i, (_, y) in enumerate(XY)]
    xy.sort()
    yx.sort()
    d = {}
    x1, i1 = xy[0]
    for x, i in xy[1:]:
        t = (i1, i) if i1 < i else (i, i1)
        d[t] = min(abs(x1 - x), d.get(t, M))
        x1, i1 = x, i
    x1, i1 = yx[0]
    for x, i in yx[1:]:
        t = (i1, i) if i1 < i else (i, i1)
        d[t] = min(abs(x1 - x), d.get(t, M))
        x1, i1 = x, i
    row = list(map(itemgetter(0), d.keys()))
    col = list(map(itemgetter(1), d.keys()))
    c = csr_matrix((list(d.values()), (row, col)), shape=(N, N))
    a = minimum_spanning_tree(c, overwrite=True)
    return int(a.sum())

print(main())