Buggy python submission (verdict: Time Limit Exceeded):
from heapq import heappop,heappush

n = int(input())
p = []
for i in range(n):
    x,y = map(int,input().split())
    p.append((i,x,y))

e = [[] for _ in range(n)]

p = sorted(p,key=lambda x:x[1])
n0,x0,y0 = p[0]
for i in range(n-1):
    n1,x1,y1 = p[i+1]
    e[n0].append([min(abs(x1-x0),abs(y1-y0)),n1])
    e[n1].append([min(abs(x1-x0),abs(y1-y0)),n0])
    n0,x0,y0 = n1,x1,y1

p = sorted(p,key=lambda x:x[2])
n0,x0,y0 = p[0]
for i in range(n-1):
    n1,x1,y1 = p[i+1]
    e[n0].append([min(abs(x1-x0),abs(y1-y0)),n1])
    e[n1].append([min(abs(x1-x0),abs(y1-y0)),n0])
    n0,x0,y0 = n1,x1,y1

def Prim(n,edge):
    #edge[source] = [[cost_1,target_1],[cost_2,target_2],...]
    used = [False] * n
    q = []
    for e in edge[0]:
        heappush(q,e)
    used[0] = True
    res = 0
    while q:
        c,v = heappop(q)
        if used[v]:
            continue
        used[v] = True
        for e in edge[v]:
            if not used[e[1]]:
                heappush(q,e)
        res += c
    return res

print(Prim(n,e))

Fixed submission:
import sys
input = sys.stdin.readline

from heapq import heappop,heappush

n = int(input())
p = []
for i in range(n):
    x,y = map(int,input().split())
    p.append((i,x,y))

e = [[] for _ in range(n)]

p = sorted(p,key=lambda x:x[1])
n0,x0,y0 = p[0]
for i in range(n-1):
    n1,x1,y1 = p[i+1]
    e[n0].append([min(abs(x1-x0),abs(y1-y0)),n1])
    e[n1].append([min(abs(x1-x0),abs(y1-y0)),n0])
    n0,x0,y0 = n1,x1,y1

p = sorted(p,key=lambda x:x[2])
n0,x0,y0 = p[0]
for i in range(n-1):
    n1,x1,y1 = p[i+1]
    e[n0].append([min(abs(x1-x0),abs(y1-y0)),n1])
    e[n1].append([min(abs(x1-x0),abs(y1-y0)),n0])
    n0,x0,y0 = n1,x1,y1

def Prim(n,edge):
    #edge[source] = [[cost_1,target_1],[cost_2,target_2],...]
    used = [False] * n
    q = []
    #e = [cost,target]
    for e in edge[0]:
        heappush(q,e)
    used[0] = True
    res = 0
    while q:
        c,v = heappop(q)
        if used[v]:
            continue
        used[v] = True
        for e in edge[v]:
            if not used[e[1]]:
                heappush(q,e)
        res += c
    return res

print(Prim(n,e))

Buggy python submission (verdict: Time Limit Exceeded):
from heapq import heappop,heappush

n = int(input())

p = []

for i in range(n):
    x,y = map(int,input().split())
    p.append((i,x,y))

e = [[] for _ in range(n)]

p = sorted(p,key=lambda x:x[1])
for i in range(n-1):
    e[p[i][0]].append([abs(p[i+1][1]-p[i][1]),p[i+1][0]])
    e[p[i+1][0]].append([abs(p[i+1][1]-p[i][1]),p[i][0]])

p = sorted(p,key=lambda x:x[2])
for i in range(n-1):
    e[p[i][0]].append([abs(p[i+1][2]-p[i][2]),p[i+1][0]])
    e[p[i+1][0]].append([abs(p[i+1][2]-p[i][2]),p[i][0]])

def Prim(n,edge):
    used = [False] * n
    q = []
    #e = [cost,target]
    for e in edge[0]:
        heappush(q,e)
    used[0] = True
    res = 0
    while q:
        c,v = heappop(q)
        if used[v]:
            continue
        used[v] = True
        for e in edge[v]:
            if not used[e[1]]:
                heappush(q,e)
        res += c
    return res

print(Prim(n,e))

Fixed submission:
import sys
input = sys.stdin.readline

from heapq import heappop,heappush

n = int(input())
p = []
for i in range(n):
    x,y = map(int,input().split())
    p.append((i,x,y))

e = [[] for _ in range(n)]

p = sorted(p,key=lambda x:x[1])
n0,x0,y0 = p[0]
for i in range(n-1):
    n1,x1,y1 = p[i+1]
    e[n0].append([min(abs(x1-x0),abs(y1-y0)),n1])
    e[n1].append([min(abs(x1-x0),abs(y1-y0)),n0])
    n0,x0,y0 = n1,x1,y1

p = sorted(p,key=lambda x:x[2])
n0,x0,y0 = p[0]
for i in range(n-1):
    n1,x1,y1 = p[i+1]
    e[n0].append([min(abs(x1-x0),abs(y1-y0)),n1])
    e[n1].append([min(abs(x1-x0),abs(y1-y0)),n0])
    n0,x0,y0 = n1,x1,y1

def Prim(n,edge):
    #edge[source] = [[cost_1,target_1],[cost_2,target_2],...]
    used = [False] * n
    q = []
    #e = [cost,target]
    for e in edge[0]:
        heappush(q,e)
    used[0] = True
    res = 0
    while q:
        c,v = heappop(q)
        if used[v]:
            continue
        used[v] = True
        for e in edge[v]:
            if not used[e[1]]:
                heappush(q,e)
        res += c
    return res

print(Prim(n,e))