#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, a = 0;
  string s;
  cin >> n >> s;
  for (int i = 0; i < n; i += 2) {
    if (s[i] == s[i + 1]) {
      ++a;
      if (s[i] == 'a') {
        s[i] = 'b';
      } else {
        s[i] = 'a';
      }
    }
  }
  cout << a << endl << s;
}
