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

from queue import PriorityQueue
from decimal import *


def dist(i, j, xy):
    x1, y1 = xy[i]
    x2, y2 = xy[j]
    d = Decimal((x1-x2)**2+(y1-y2)**2).sqrt()
    if d - int(d) > 0:
        return int(d)+10-(int(d) % 10)
    else:
        if int(d) % 10 == 0:
            return int(d)
        else:
            return int(d)+10-(int(d) % 10)



def main():
    n = int(input())
    xy = [list(map(int, input().split())) for _ in range(n)]
    L = [[dist(i, j, xy) for i in range(n)] for j in range(n)]

    que = PriorityQueue()
    inf = 10**19
    S, G = 0, n-1
    que.put([0, [S]])
    ans = inf
    dm = [inf] * n
    while not que.empty():
        e, v = que.get()
        e, t = int(e), int(v[-1])
        dm[t] = min(dm[t], e)
        if t == G:
            ans = min(e, ans)
            continue
        for i in range(n):
            if i == t or dm[i] <= max(L[t][i], e):
                continue
            que.put([max(L[t][i], e), v+[i]])

    print(ans)
    return

if __name__ == '__main__':
    main()