class UnionFind:
    def __init__(self,n):
        self.n=n
        self.parent=[-1]*n

    def root(self,x):
        if self.parent[x]<0:return x
        self.parent[x]=self.root(self.parent[x])
        return self.parent[x]
    
    def merge(self,x,y):
        x,y=self.root(x),self.root(y)
        if x==y:return 
        if -self.parent[x]<-self.parent[y]:
            x,y=y,x
        self.parent[x]+=self.parent[y]
        self.parent[y]=x
    
    def same(self,x,y):
        return self.root(x)==self.root(y)
    
    def size(self,x):
        return -self.parent[self.root(x)]
    
    def groups(self):
        members=[[] for _  in range(self.n)]
        for v in range(self.n):
            members[self.root(v)].append(v)
        res=[]
        for member in members:
            if member:res.append(member)
        return res



n=int(input())
xy=[list(map(int,input().split())) for _ in range(n)]

def dist(a,b):
    return abs(a[0]-b[0])**2+abs(a[1]-b[1])**2

def check(x):
    uf=UnionFind(n)
    for i in range(n-1):
        for j in range(i+1,n):
            if dist(xy[i],xy[j])<=x**2:
                uf.merge(i,j)
    
    return uf.same(0,n-1)
    

ng,ok=-1,10**9
while ok-ng>1:
    mid=(ok+ng)//2
    if check(10*mid):
        ok=mid
    else:
        ng=mid

print(10*ok)