#include <bits/stdc++.h>
using namespace std;
void solve() {
  int n;
  cin >> n;
  string s;
  cin >> s;
  int r = 0;
  for (int i = 0; i < n; i += 2) {
    if (s[i] == s[i + 1]) {
      r++;
      s[i] = 'a';
      s[i + 1] = 'b';
    }
  }
  cout << r << "\n" << s << "\n";
}
int main() { solve(); }
