#include<iostream>
#include<cstring>
#include<vector>
using namespace std;
vector<string> ans;
int n,Hr,Hb;
string str;

bool dfs(int pos,int fg,int nb,int nr)
{
   
    if(nb>Hb||nr>Hr) return false;
    if(pos==n+1)
    {
        ans.push_back(str);
        if(ans.size()==100) return true;
        else return false;
      
    }

    int b=nb,r=nr;

    if(fg%2) r++;
    else b++;

    str[pos-1]='b';
    if(dfs(pos+1,fg,b,r)) return true;

    b=nb,r=nr;
    if(fg%2) b++;
    else r++;

    str[pos-1]='r';
    if(dfs(pos+1,fg^1,b,r))  return true;
    
   
    return false;
}

signed main()
{
    ios::sync_with_stdio(0); cin.tie(0);
    cin>>n; 
    for(int i=0;i<n;i++) str+='b';

   
    if(n%2==0) Hr=(n+1)/2+1;
    else Hr=(n+1)/2;

    Hb=Hr-1;
    


    dfs(1,0,0,0);
   
   
    cout<<1LL*Hr*(n-Hr+1)<<"\n";
    for(auto c:ans) cout<<c<<"\n";
    
}