import sys; input = sys.stdin.buffer.readline
sys.setrecursionlimit(10**7)
from collections import defaultdict
con = 10 ** 9 + 7; INF = float("inf")
import math

def getlist():
	return list(map(int, input().split()))

class UnionFind:
	def __init__(self, n):
		self.par = [i for i in range(n + 1)]
		self.rank = [0] * (n + 1)

	def find(self, x):
		if self.par[x] == x:
			return x
		else:
			self.par[x] = self.find(self.par[x])
			return self.par[x]

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

	def union(self, x, y):
		x = self.find(x); y = self.find(y)
		if self.rank[x] < self.rank[y]:
			self.par[x] = y
		else:
			self.par[y] = x
			if self.rank[x] == self.rank[y]:
				self.rank[x] += 1



#処理内容
def main():
	N = int(input())
	UF = UnionFind(N)
	node = []
	edge = []
	for i in range(N):
		X, Y = getlist()
		node.append([X, Y])

	for i in range(N):
		for j in range(i + 1, N):
			x1, y1 = node[i]
			x2, y2 = node[j]
			edge.append([math.sqrt((x1 - x2) ** 2 + (y1 - y2) ** 2) + 9.999999, i, j])

	edge.sort()
	ans = INF
	for dist, i, j in edge:
		UF.union(i, j)
		if UF.same_check(0, N - 1):
			ans = int(dist // 10) * 10
			break

	print(ans)


if __name__ == '__main__':
	main()