from collections import deque, defaultdict, Counter
from bisect import bisect_left, bisect_right
from itertools import permutations, combinations
from functools import cmp_to_key, cache
from heapq import heappop, heappush
import math, sys
import pypyjit
pypyjit.set_param('max_unroll_recursion=-1')
sys.setrecursionlimit(10**7)
_int = lambda x: int(x)-1
MOD = 998244353
INF = 1<<62
Yes, No = "Yes", "No"

M = 200000
X = int(input())
def prime(num):
    num = int(num)
    p = []
    if num < 2: return p
    p.append(2)
    memo = [i%2 for i in range(num+1)]
    for i in range(3, num+1, 2):
        if memo[i] == 0: continue
        p.append(i)
        for j in range(i, num+1, i):
            memo[j] = 0
    return p
P = prime(M)
# print(P)
if X < 6:
    print(X+1)
    for i in range(X):
        print(1, i+2)
    C = ["b"]+["g"]*X
    print(*C)
    exit()
cur = 1
last = -1
UV = []
C = []
for p in P:
    while X%p == 0:
        if cur+p > M:
            print(-1)
            exit()
        par = cur
        if last != -1:
            UV.append((last, par))
        last = par
        C.append("b")
        cur += p+1
        for i in range(p):
            UV.append((par, par+i+1))
            C.append("g")
        X //= p
if X != 1:
    print(-1)
    exit()
print(len(C))
for u, v in UV:
    print(u, v)
print(*C)