X = int(input())

M = 2*10**5

def prime_factorize(n):
    res = []
    for i in range(2, M+1):
        if i*i > n:
            break
        if n % i != 0:
            continue
        while n % i == 0:
            n //= i
            res.append(i)
    if n != 1 or len(res) == 0:
        res.append(n)
    return res

pf = prime_factorize(X)
cnt2 = sum(1 for x in pf if x == 2)
pf.extend([4]*(cnt2//2))
pf = pf[cnt2//2:]

if len(pf) + sum(pf) > M:
    print(-1)
    exit()

print(len(pf) + sum(pf))
c = ['b']*len(pf) + ['g']*sum(pf)
for i in range(len(pf)-1):
    print(i+1, i+2)

ind = len(pf)
for i in range(len(pf)):
    for j in range(pf[i]):
        print(i+1, ind+j+1)
    ind += pf[i]
print(*c)