#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, c = 0, i;
  cin >> n;
  string s;
  cin >> s;
  string s1;
  for (i = 0; i < n; i = i + 2) {
    if ((s[i] == 'a' && s[i + 1] == 'b') || (s[i] == 'b' && s[i + 1] == 'a')) {
      s1 += s[i];
      s1 += s[i + 1];
    } else if (s[i] == 'a' && s[i + 1] == 'a') {
      s1 += s[i];
      s1 += 'b';
      c++;
    } else {
      c++;
      s1 += s[i];
      s1 += 'a';
    }
  }
  cout << c << endl << s1;
}
