#include #define For(i, a, b) for(long long i = a; i < b; i++) #define rep(i, n) For(i, 0, n) #define rFor(i, a, b) for(long long i = a; i >= b; i--) #define ALL(v) (v).begin(), (v).end() #define rALL(v) (v).rbegin(), (v).rend() using namespace std; using lint = long long; using ld = long double; namespace fastprime { template T modpow(T a, T b, T mod) { T cur = a % mod, res = 1 % mod; while (b) { if (b & 1) { res = (res * cur) % mod; } cur = (cur * cur) % mod; b >>= 1; } return res; } bool MillerRabin(long long n) { if (n <= 1) { return false; } if (n == 2 || n == 7 || n == 61) { return true; } if (n % 2 == 0) { return false; } vector A; if (n < 4759123141) { A = {2, 7, 61}; } else { A = {2, 325, 9375, 28178, 450775, 9780504, 1795265022}; } long long s = 0, d = n - 1; while (d % 2 == 0) { s++; d >>= 1; } for (auto a : A) { if (a % n == 0) { return true; } long long x = modpow<__int128_t>(a, d, n); if (x == 1) { continue; } bool ok = false; for (int i = 0; i < s; i++) { if (x == n - 1) { ok = true; break; } x = (__int128_t)x * x % n; } if (!ok) { return false; } } return true; } long long gcd(long long x, long long y) { if (y == 0) { return x; } return gcd(y, x % y); } unsigned int xorshift() { static unsigned int x = 123456789, y = 362436069, z = 521288629, w = 88675123; unsigned int t = (x ^ (x << 11)); x = y; y = z; z = w; return (w = (w ^ (w >> 19)) ^ (t ^ (t >> 8))); } long long Pollard(long long n) { if (n % 2 == 0) { return 2LL; } if (MillerRabin(n)) { return n; } long long i = 0; while (true) { i++; long long r = xorshift(); auto f = [&](long long x) { return (__int128_t(x) * x + r) % n; }; long long x = i, y = f(x); while (true) { long long p = gcd(abs(y - x + n), n); if (p == 0 || p == n) { break; } if (p != 1) { return p; } x = f(x); y = f(f(y)); } } } vector prime_factorize(long long n) { if (n == 1) { return {}; } long long p = Pollard(n); if (p == n) { return {p}; } vector l = prime_factorize(p); vector r = prime_factorize(n / p); for (auto x : r) { l.emplace_back(x); } sort(l.begin(), l.end()); return l; } vector divisors(long long n) { if (n == 1) { return {1LL}; } auto divisor_dfs = [&](auto divisor_dfs, vector> &p, long long t, int cur, vector &res) -> void { if (cur == p.size()) { res.emplace_back(t); return; } divisor_dfs(divisor_dfs, p, t, cur + 1, res); for (int i = 0; i < p[cur].second; i++) { t *= p[cur].first; divisor_dfs(divisor_dfs, p, t, cur + 1, res); } }; vector res, pf = prime_factorize(n); vector> p; long long cnt = 1, now = pf[0]; for (int i = 1; i < (int)pf.size(); i++) { if (pf[i] == now) { cnt++; } else { p.emplace_back(now, cnt); now = pf[i]; cnt = 1; } } p.emplace_back(now, cnt); divisor_dfs(divisor_dfs, p, 1, 0, res); sort(res.begin(), res.end()); return res; } } // namespace fastprime using namespace fastprime; int main() { lint x; cin >> x; if (x == 1) { cout << 2 << endl << "1 2" << endl << "b g" << endl; return 0; } auto ps = prime_factorize(x); lint cnt_2 = 0; for (auto p : ps) { if (p == 2) { cnt_2++; } } vector ans; rep(i, cnt_2 % 2) { ans.emplace_back(2); } rep(i, cnt_2 / 2) { ans.emplace_back(4); } for (auto p : ps) { if (p > 2) { ans.emplace_back(p); } } lint n = accumulate(ALL(ans), 0LL) + (lint)ans.size(); if (n > 200000) { cout << -1 << endl; return 0; } cout << n << endl; vector col(n + 1); rep(i, (lint)ans.size() - 1) { cout << i + 1 << " " << i + 2 << endl; } For(i, 1, (lint)ans.size() + 1) { col[i] = 'b'; } lint cur = ans.size(); rep(i, (lint)ans.size()) { rep(_, ans[i]) { cur++; cout << i + 1 << " " << cur << endl; col[cur] = 'g'; } } For(i, 1, n + 1) { cout << col[i] << " "; } cout << endl; }