#include <bits/stdc++.h>
int main() {
  long n;
  std::cin >> n;
  std::string s;
  std::cin >> s;
  long cnt(0);
  for (long p = 1; p < s.size(); p += 2) {
    if (s[p] != s[p - 1]) {
      continue;
    }
    s[p] = (s[p - 1] == 'a' ? 'b' : 'a');
    ++cnt;
  }
  std::cout << cnt << std::endl;
  std::cout << s << std::endl;
  return 0;
}
