import sys
from bisect import bisect_left
from math import isqrt, inf
from typing import List, Tuple


def int1(x: str, /): return int(x) - 1


def input(): return sys.stdin.readline().rstrip('\n')


def dbg(*args, **kwargs):
    print(*(repr(arg) for arg in args), *(f'{k}: {repr(v)}' for k, v in kwargs.items()),
          sep='; ', file=sys.stderr, flush=True)


def dx(a, b):
    ax, ay = a
    bx, by = b
    sq = (ax - bx) ** 2 + (ay - by) ** 2
    return 0 if sq == 0 else (isqrt(sq - 1) // 10 + 1) * 10


def main():
    n = int(input())
    xy = [tuple(map(int, input().split())) for _ in range(n)]
    d = [[0] * n for _ in range(n)]
    for i in range(n):
        for j in range(i):
            d[i][j] = d[j][i] = dx(xy[i], xy[j])

    vis = [False] * n
    vis[0] = True
    dis = d[0][:]
    ans = 0
    while True:
        mini = None
        for i in range(n):
            if not vis[i]:
                if mini is None or dis[mini] > dis[i]:
                    mini = i

        ans = max(ans, dis[mini])
        if mini == n - 1:
            return ans

        for i in range(n):
            dis[i] = min(dis[i], d[mini][i])
        vis[mini] = True


def _start():
    ret = main()

    if ret is not None:
        if isinstance(ret, List) or isinstance(ret, Tuple):
            print(*ret)
        else:
            print(ret)


if __name__ == '__main__':
    _start()