n = int(input())
dp = [i * (i + 1) // 2 for i in range(10**6+2)]

Ans = []

l = 0
r = 0
N = 10 ** 6 + 1
while l < N:
    if r < N and (dp[r] - dp[l]) * (dp[r] + dp[l]) < n:
        r += 1
    else:
        if (dp[r] - dp[l]) * (dp[r] + dp[l]) == n:
            Ans.append((l+1, r))
        l += 1

print(len(Ans))
for l, r in Ans:
    print(l, r)