#include <bits/stdc++.h>
using namespace std;
int visited[10000] = {0};
vector<int> adj[10000];
void solve() {
  int n;
  cin >> n;
  string a;
  cin >> a;
  int count = 0;
  for (int i = 1; i < a.length(); i += 2) {
    if (a[i] == a[i - 1] && a[i] == 'b') {
      count++;
      a[i] = 'a';
    } else if (a[i] == a[i - 1] && a[i] == 'a') {
      count++;
      a[i] = 'b';
    }
  }
  cout << count << endl;
  cout << a;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  solve();
  return 0;
}
