inf = 2**32
def warshall():
    for k in range(N):
        for i in range(N):
            for j in range(N):
                G[i][j] = min(G[i][j],G[i][k]+G[k][j])
                
def S(a,b):
    ax,ay = a; bx,by = b
    return (bx-ax)**2+(by-ay)**2
    
N = int(raw_input())
XY = [map(int,raw_input().split()) for _ in range(N)]
G = [[inf]*N for _ in range(N)]
for i in range(N-1):
    for j in range(i+1,N):
        if S(XY[i],XY[j]) <= 100:
            G[i][j] = G[j][i] = 1
warshall()

ans = 0
for i in range(N-1):
    for j in range(i+1,N):
        if G[i][j] < inf:
            ans = max(ans,S(XY[i],XY[j])**0.5+2)
print ans