Problem: Find \displaystyle{\sum_{a=1}^{K}\sum_{b=1}^{K}\sum_{c=1}^{K} \gcd(a,b,c)}.  Here \gcd(a,b,c) denotes the greatest common divisor of a, b, and c.

Submission attempts (in order):
K = int(input())

ans = 0
for a in range(1, K+1):
    for b in range(1, K+1):
        for c in range(1, K+1):
            ans += math.gcd(math.gcd(a,b),c)
print(ans)
exit()


import math, string, itertools, fractions, heapq, collections, re,  array, bisect, sys, random, time, copy, functools
sys.setrecursionlimit(10**7)
from queue import PriorityQueue
from fractions import gcd
inf = 10 ** 20
eps = 1.0 / 10**10
mod = 10**9+7
dd = [(-1, 0), (0, 1), (1, 0), (0, -1)]
ddn = [(-1, 0), (-1, 1), (0, 1), (1, 1), (1, 0), (1, -1), (0, -1), (-1, -1)]
def LI(): return [int(x) for x in sys.stdin.readline().split()]
def LI_(): return [int(x)-1 for x in sys.stdin.readline().split()]
def LF(): return [float(x) for x in sys.stdin.readline().split()]
def LS(): return sys.stdin.readline().split()
def _I(): return int(sys.stdin.readline())
def _F(): return float(sys.stdin.readline())
def _pf(s): return print(s, flush=True)
def gcd(*numbers):
    return functools.reduce(math.gcd, numbers)
def make_divisors(n):
    divisors = []
    for i in range(1, int(n**0.5)+1):
        if n % i == 0:
            divisors.append(i)
            if i != n // i:
                divisors.append(n//i)

    divisors.sort(reverse=True)
    return divisors

K = _I()

ans = 0

for i in range(1, K+1):
    for j in range(1, K+1):
        for k in range(1, K+1):
            ans += math.gcd(math.gcd(i,j),k)
print(ans)
exit()


import math, string, itertools, fractions, heapq, collections, re,  array, bisect, sys, random, time, copy, functools
sys.setrecursionlimit(10**7)
from queue import PriorityQueue
from fractions import gcd
inf = 10 ** 20
eps = 1.0 / 10**10
mod = 10**9+7
dd = [(-1, 0), (0, 1), (1, 0), (0, -1)]
ddn = [(-1, 0), (-1, 1), (0, 1), (1, 1), (1, 0), (1, -1), (0, -1), (-1, -1)]
def LI(): return [int(x) for x in sys.stdin.readline().split()]
def LI_(): return [int(x)-1 for x in sys.stdin.readline().split()]
def LF(): return [float(x) for x in sys.stdin.readline().split()]
def LS(): return sys.stdin.readline().split()
def _I(): return int(sys.stdin.readline())
def _F(): return float(sys.stdin.readline())
def _pf(s): return print(s, flush=True)
def gcd(*numbers):
    return functools.reduce(math.gcd, numbers)
def make_divisors(n):
    divisors = []
    for i in range(1, int(n**0.5)+1):
        if n % i == 0:
            divisors.append(i)
            if i != n // i:
                divisors.append(n//i)

    divisors.sort(reverse=True)
    return divisors

K = _I()

ans = 0

for i in range(1, K+1):
    for j in range(1, K+1):
        for k in range(1, K+1):
            ans += gcd(gcd(i,j),k)
print(ans)
exit()


import math, string, itertools, fractions, heapq, collections, re,  array, bisect, sys, random, time, copy, functools
sys.setrecursionlimit(10**7)
from queue import PriorityQueue
from fractions import gcd
inf = 10 ** 20
eps = 1.0 / 10**10
mod = 10**9+7
dd = [(-1, 0), (0, 1), (1, 0), (0, -1)]
ddn = [(-1, 0), (-1, 1), (0, 1), (1, 1), (1, 0), (1, -1), (0, -1), (-1, -1)]
def LI(): return [int(x) for x in sys.stdin.readline().split()]
def LI_(): return [int(x)-1 for x in sys.stdin.readline().split()]
def LF(): return [float(x) for x in sys.stdin.readline().split()]
def LS(): return sys.stdin.readline().split()
def _I(): return int(sys.stdin.readline())
def _F(): return float(sys.stdin.readline())
def _pf(s): return print(s, flush=True)
def gcd(*numbers):
    return functools.reduce(math.gcd, numbers)
def make_divisors(n):
    divisors = []
    for i in range(1, int(n**0.5)+1):
        if n % i == 0:
            divisors.append(i)
            if i != n // i:
                divisors.append(n//i)

    divisors.sort(reverse=True)
    return divisors

K = _I()

ans = 0

for i in range(1, K+1):
    for j in range(1, K+1):
        for k in range(1, K+1):
            ans += gcd(i,j,k)
print(ans)
exit()


import math, string, itertools, fractions, heapq, collections, re,  array, bisect, sys, random, time, copy, functools
sys.setrecursionlimit(10**7)
from queue import PriorityQueue
from fractions import gcd
inf = 10 ** 20
eps = 1.0 / 10**10
mod = 10**9+7
dd = [(-1, 0), (0, 1), (1, 0), (0, -1)]
ddn = [(-1, 0), (-1, 1), (0, 1), (1, 1), (1, 0), (1, -1), (0, -1), (-1, -1)]
def LI(): return [int(x) for x in sys.stdin.readline().split()]
def LI_(): return [int(x)-1 for x in sys.stdin.readline().split()]
def LF(): return [float(x) for x in sys.stdin.readline().split()]
def LS(): return sys.stdin.readline().split()
def _I(): return int(sys.stdin.readline())
def _F(): return float(sys.stdin.readline())
def _pf(s): return print(s, flush=True)

#      return functools.reduce(math.gcd, numbers)











K = _I()

ans = 0
for i in range(1, K+1):
    for j in range(1, K+1):
        for k in range(1, K+1):
            ans += math.gcd(math.gcd(i,j),k)
print(ans)
exit()


import math, string, itertools, fractions, heapq, collections, re,  array, bisect, sys, random, time, copy, functools
sys.setrecursionlimit(10**7)
from queue import PriorityQueue
from fractions import gcd
inf = 10 ** 20
eps = 1.0 / 10**10
mod = 10**9+7
dd = [(-1, 0), (0, 1), (1, 0), (0, -1)]
ddn = [(-1, 0), (-1, 1), (0, 1), (1, 1), (1, 0), (1, -1), (0, -1), (-1, -1)]
def LI(): return [int(x) for x in sys.stdin.readline().split()]
def LI_(): return [int(x)-1 for x in sys.stdin.readline().split()]
def LF(): return [float(x) for x in sys.stdin.readline().split()]
def LS(): return sys.stdin.readline().split()
def _I(): return int(sys.stdin.readline())
def _F(): return float(sys.stdin.readline())
def _pf(s): return print(s, flush=True)

#      return functools.reduce(math.gcd, numbers)











K = _I()

ans = 0
for a in range(1, K+1):
    for b in range(1, K+1):
        for c in range(1, K+1):
            ans += math.gcd(math.gcd(a,b),c)
print(ans)
exit()


from math import gcd
K = int(input())

ans = 0
for a in range(1, K+1):
    for b in range(1, K+1):
        for c in range(1, K+1):
            ans += gcd(gcd(a,b),c)
print(ans)
exit()


Verdicts: Runtime Error

Time Limit Exceeded

Time Limit Exceeded

Time Limit Exceeded

Time Limit Exceeded

Time Limit Exceeded

Accepted