from math import ceil
from heapq import *

N = int(input())
XYT = [list(map(int, input().split())) for _ in range(N)]
dist = [[0] * N for _ in range(N)]
for i in range(N):
    x1, y1, t1 = XYT[i]
    for j in range(i, N):
        x2, y2, t2 = XYT[j]
        if t1 == t2:
            dist[i][j] = dist[j][i] = ((x1 - x2) ** 2 + (y1 - y2) ** 2) ** 0.5
        else:
            dist[i][j] = dist[j][i] = abs((x1 ** 2 + y1 ** 2) ** 0.5 - (x2 ** 2 + y2 ** 2) ** 0.5)

for i in range(N):
    for j in range(N):
        for k in range(N):
            dist[i][j] = min(dist[i][j], max(dist[i][k], dist[k][j]))

print(ceil(dist[0][N - 1] ** 2))