X=int(input())
g=[]
while X % 4 == 0:
    g.append(4)
    X //= 4
for i in range(2, 200000):
    while X % i==0:
        g.append(i)
        X //= i
if X != 1:
    print(-1)
    exit()
if len(g) == 0:
    g.append(1)
if sum(g) + len(g) > 200000:
	print(-1)
	exit()
print(sum(g) + len(g))
c=["b"] * len(g) + ["g"] * sum(g)
pos=len(g) + 1
for i in range(len(g)):
    if i != 0:
        print(i, i + 1)
    for j in range(g[i]):
        print(i + 1, pos)
        pos += 1
print(*c)