X = int(input())
s = []
if X == 1:
	s += [1]
for i in range(2, 200001):
	if X % i == 0:
		c = 0
		while X % i == 0:
			X //= i
			c += 1
		if i == 2:
			s += [4] * (c // 2) + [2] * (c % 2)
		else:
			s += [i] * c
N = len(s) + sum(s)
if X == 1 and N <= 200000:
	print(N)
	t = len(s)
	for i in range(len(s) - 1):
		print(i + 1, i + 2)
	for i in range(len(s)):
		for j in range(t, t + s[i]):
			print(i + 1, j + 1)
		t += s[i]
	print(' '.join(['b'] * len(s) + ['g'] * sum(s)))
else:
	print(-1)