def gcd(a, b):
return gcd(b, a % b) if b > 0 else a
def lcm(a, b):
return a * b // gcd(a, b)
n = int(input())
l = [*map(int, input().split())]
p = l[0]
for i in range(1, n):
p = lcm(p, l[i])
c = 0
for i in range(n):
c += p // l[i]
tmp = gcd(p, c)
p //= tmp
c //= tmp
print(f"{p}/{c}")