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