#include <bits/stdc++.h>
using namespace std;
int main() {
  int t;
  while (cin >> t) {
    string a;
    cin >> a;
    int s = 0;
    for (int i = 0; i < t - 1;) {
      if (a.at(i) == a.at(i + 1)) {
        if (a.at(i) == 'a')
          a.at(i) = 'b';
        else
          a.at(i) = 'a';
        s++;
      }
      i += 2;
      if (i >= a.size()) break;
    }
    cout << s << endl << a << endl;
  }
  return 0;
}
