x = int(input())
d = list()
for i in range(3, 2*10**5+1):
    while x % i == 0:
        x //= i
        d.append(i)
if x%2 == 0:
    x //= 2
    d.append(2)

if x != 1 or len(d)==0:
    d.append(x)

ans = 0
for i in range(len(d)):
    ans += d[i] + 1

if ans > 2*10**5:
    exit(print(-1))

print(ans)
for i in range(len(d)-1):
    print(i+1, i+2)

id = len(d) + 1
for i in range(len(d)):
    for j in range(d[i]):
        print(i+1, id)
        id += 1

print(*("b"*len(d) + "g"*(ans-len(d))))