points = []
for line in open("input"):
    x,y,z = map(int,line.split(','))
    points.append((x,y,z))

import math
def dist(p,q):
    return math.sqrt(sum((x-y)**2 for x,y in zip(p,q)))

import random
n = len(points)
min_dist = float('inf')
#for _ in range(n):
#    a = random.choice(points)
for a in points:
    b = random.choice(points)
    d = dist(a,b)
    if d == 0:
        continue
    min_dist = min(d,min_dist)

print(min_dist)