#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vi = vector<int>;
using pi = pair<int, int>;
const int N = 100;
void setIO(string name = "") {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  if ((int)(name).size()) {
    freopen((name + ".in").c_str(), "r", stdin);
    freopen((name + ".out").c_str(), "w", stdout);
  }
}
int main() {
  setIO();
  int n;
  cin >> n;
  string second;
  cin >> second;
  int ans = 0;
  for (int i = 0; i < n; i += 2) {
    if (second.at(i) == second.at(i + 1)) {
      second[i + 1] = second.at(i) == 'a' ? 'b' : 'a';
      ans++;
    }
  }
  cout << ans << "\n" << second << "\n";
}
