from math import ceil
from heapq import *

N = int(input())
RXYT = []
for i in range(N):
    x, y, t = map(int, input().split())
    r = (x ** 2 + y ** 2) ** 0.5
    RXYT.append((r, x, y, t))

E = [[] for _ in range(N)]
for i in range(N - 1):
    r1, x1, y1, t1 = RXYT[i]
    for j in range(i + 1, N):
        r2, x2, y2, t2 = RXYT[j]
        if t1 == t2:
            tmp = (x1 - x2) ** 2 + (y1 - y2) ** 2
            E[i].append((j, tmp))
            E[j].append((i, tmp))
        else:
            tmp = (r1 - r2) ** 2
            E[i].append((j, tmp))
            E[j].append((i, tmp))

D = [float('inf')] * N
D[0] = 0
q = [(0, 0)]
while len(q) > 0:
    d, u = heappop(q)
    for i in E[u]:
        a, b = i
        #if d > D[u]: continue
        tmp = max(D[u], b)
        if D[a] > tmp:
            D[a] = tmp
            heappush(q, (D[a], a))
#print(D)
print(ceil(D[N - 1]))