from decimal import Decimal
import heapq
import math

class UnionFind():
    def __init__(self, n):
        self.n = n
        self.parents = [-1] * n

    def find(self, x):
        if self.parents[x] < 0:
            return x
        else:
            self.parents[x] = self.find(self.parents[x])
            return self.parents[x]

    def union(self, x, y):
        x = self.find(x)
        y = self.find(y)
        if x == y:
            return
        if self.parents[x] > self.parents[y]:
            x, y = y, x
        self.parents[x] += self.parents[y]
        self.parents[y] = x

    def same(self, x, y):
        return self.find(x) == self.find(y)



N = int(input())
XYT = [list(map(int, input().split())) for _ in range(N)]
D = []
for i in range(N):
    D.append(Decimal(XYT[i][0]**2+XYT[i][1]**2)**Decimal('0.5'))

XY = [[0]*N for _ in range(N)]
for i in range(N):
    for j in range(i+1,N):
        XY[i][j]=(D[i]-D[j])**Decimal('2')

H = []
for i,xyti in enumerate(XYT):
    for j,xytj in enumerate(XYT[i+1:],start=i+1):
        if xyti[2]==xytj[2]:
            xi,yi,ti = xyti
            xj,yj,tj = xytj
            heapq.heappush(H,((xi-xj)**2+(yi-yj)**2,i,j))
        else:
            heapq.heappush(H,(XY[i][j],i,j))
uf = UnionFind(N)
while not uf.same(0,N-1):
    ans,i,j = heapq.heappop(H)
    uf.union(i,j)
print(math.ceil(ans))