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