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