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