import sys
readline=sys.stdin.readline
from collections import defaultdict

class UnionFind:
    def __init__(self,N,label=None,f=None,weighted=False):
        self.N=N
        self.parents=[None]*self.N
        self.size=[1]*self.N
        self.roots={i for i in range(self.N)}
        self.label=label
        if self.label!=None:
            self.label=[x for x in label]
        self.f=f
        self.weighted=weighted
        if self.weighted:
            self.weight=[0]*self.N

    def Find(self,x):
        stack=[]
        while self.parents[x]!=None:
            stack.append(x)
            x=self.parents[x]
        if self.weighted:
            w=0
            for y in stack[::-1]:
                self.parents[y]=x
                w+=self.weight[y]
                self.weight[y]=w
        else:
            for y in stack[::-1]:
                self.parents[y]=x
        return x

    def Union(self,x,y,w=None):
        root_x=self.Find(x)
        root_y=self.Find(y)
        if root_x==root_y:
            if self.weighted:
                if self.weight[y]-self.weight[x]==w:
                    return True
                else:
                    return False
        else:
            if self.size[root_x]<self.size[root_y]:
                x,y=y,x
                root_x,root_y=root_y,root_x
                if self.weighted:
                    w=-w
            self.parents[root_y]=root_x
            self.size[root_x]+=self.size[root_y]
            self.roots.remove(root_y)
            if self.label!=None:
                self.label[root_x]=self.f(self.label[root_x],self.label[root_y])
            if self.weighted:
                self.weight[root_y]=w+self.weight[x]-self.weight[y]

    def Size(self,x):
        return self.size[self.Find(x)]

    def Same(self,x,y):
        return self.Find(x)==self.Find(y)

    def Label(self,x):
        return self.label[self.Find(x)]

    def Weight(self,x,y):
        root_x=self.Find(x)
        root_y=self.Find(y)
        if root_x!=root_y:
            return None
        return self.weight[y]-self.weight[x]

    def Roots(self):
        return list(self.roots)

    def Link_Components_Count(self):
        return len(self.roots)

    def __str__(self):
        linked_components=defaultdict(list)
        for x in range(self.N):
            linked_components[self.Find(x)].append(x)
        return "\n".join(f"{r}: {m}" for r,m in linked_components.items())

def Bisect_Int(ok,ng,is_ok):
    while abs(ok-ng)>1:
        mid=(ok+ng)//2
        if is_ok(mid):
            ok=mid
        else:
            ng=mid
    return ok

N=int(readline())
X,Y=[],[]
for _ in range(N):
    x,y=map(int,readline().split())
    X.append(x)
    Y.append(y)
def is_ok(x):
    UF=UnionFind(N)
    for i in range(N):
        for j in range(i+1,N):
            if (X[i]-X[j])**2+(Y[i]-Y[j])**2<=100*x**2:
                UF.Union(i,j)
    return UF.Same(0,N-1)
ans=Bisect_Int(10**9,0,is_ok)*10
print(ans)