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