#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, a, b, flag, t;
  string str;
  a = 0;
  b = 0;
  flag = 0;
  cin >> n;
  cin >> str;
  for (int i = 0; i < str.length(); i++) {
    if (str[i] == 'a') {
      a++;
    }
  }
  t = 0;
  for (int i = 0; i < str.length(); i = i + 2) {
    if (str[i] == str[i + 1]) {
      t++;
    }
  }
  cout << t << endl;
  for (int i = 0; i < str.length(); i = i + 2) {
    if (str[i] == str[i + 1]) {
      if (str[i] == 'a') {
        cout << "ba";
      } else {
        cout << "ba";
      }
    } else {
      cout << str[i] << str[i + 1];
    }
  }
  cout << endl;
  return 0;
}
