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