#include <bits/stdc++.h>
using namespace std;
#define F first
#define S second
#define R cin>>
#define ln cout<<'\n'
#define ll long long
#define in(a) insert(a)
#define pb(a) push_back(a)
#define pd(a) printf("%.12f\n",a)
#define mem(a) memset(a,0,sizeof(a))
#define all(c) (c).begin(),(c).end()
#define iter(c) __typeof((c).begin())
#define rrep(i,n) for(ll i=(ll)(n)-1;i>=0;i--)
#define REP(i,m,n) for(ll i=(ll)(m);i<(ll)(n);i++)
#define rep(i,n) REP(i,0,n)
#define tr(it,c) for(iter(c) it=(c).begin();it!=(c).end();it++)
ll check(ll n,ll m,ll x,ll y){return x>=0&&x<n&&y>=0&&y<m;}void pr(){ln;}
template<class A,class...B>void pr(const A &a,const B&...b){cout<<a<<(sizeof...(b)?" ":"");pr(b...);}
template<class A>void PR(A a,ll n){rep(i,n)cout<<(i?" ":"")<<a[i];ln;}
const ll MAX=1e9+7,MAXL=1LL<<61,dx[8]={-1,0,1,0,-1,-1,1,1},dy[8]={0,1,0,-1,-1,1,1,-1};
typedef pair<ll,ll> P;

void Main() {
  ll n;
  cin >> n;
  vector<ll> a;
  for(ll i=2; i*i<=n; i++) {
    if(i>200000) {
      pr(-1);
      return;
    }
    while(n%i==0) {
      a.pb(i);
      n/=i;
    }
  }
  if(!a.size()||n>1) a.pb(n);
  ll s=a.size();
  rep(i,a.size()) s+=a[i];
  if(s>200000) {
    pr(-1);
    return;
  }
  vector<P> v;
  rep(i,a.size()-1) v.pb(P(i+1,i+2));
  ll x=a.size()+1;
  rep(i,a.size()) {
    rep(j,a[i]) {
      v.pb(P(i+1,x));
      x++;
    }
  }
  pr(s);
  rep(i,v.size()) pr(v[i].F,v[i].S);
  rep(i,s) {
    if(i) cout << " ";
    if(i<a.size()) cout << 'b';
    else cout << 'g';
  }
  ln;
}

int main(){ios::sync_with_stdio(0);cin.tie(0);Main();return 0;}