X = int(input())

if X in (1,4):
    arr = [X]
else:
    arr = []
    for n in range(2,200001):
        while X%n == 0:
            arr.append(n)
            X //= n

if not arr: exit(print(-1))

if sum(arr) + len(arr) > 200000:
    exit(print(-1))

K = sum(arr) + len(arr)
print(K)

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

n = len(arr) + 1
for i,a in enumerate(arr):
    for _ in range(a):
        print(i+1, n)
        n += 1
c = ['b'] * len(arr) + ['g'] * (K - len(arr))
print(*c)