#!/c/Python34/python
# coding: utf-8

import heapq, math

def dist(a, b, c, d):
    return math.sqrt((a-b)*(a-b)+(c-d)*(c-d))

def main():
    n = int(input())
    x, y = [0] * n, [0] * n
    for i in range(n):
        [x[i], y[i]] = map(int, input().split())

    L = [[0] * n for _ in range(n)]
    for i in range(n):
        for j in range(i + 1, n):
            L[i][j] = L[j][i] = dist(x[i], x[j], y[i], y[j])

    q = [[0, [0]]]
    d = {}
    while len(q) > 0:
        e, v = heapq.heappop(q)
        t = v[-1]
        if t not in d:
            d[t] = True
            if t == n - 1:
                break
            for i in range(n):
                heapq.heappush(q, [max(L[t][i], e), v+[i]])

    print(int(e) + (10 - int(e) % 10))
    return

if __name__ == '__main__':
    main()