#include <bits/stdc++.h>
using namespace std;
using i1 = int;
const long long int MAX = 1e4 + 5;
const long long int mod = 1e9 + 7;
vector<int> v;
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  int n, c = 0;
  cin >> n;
  string s;
  cin >> s;
  for (int i = 0; s[i]; i += 2) {
    if (s[i] == 'a' and s[i + 1] == 'b')
      continue;
    else if (s[i] == 'b' and s[i + 1] == 'a')
      continue;
    else
      c++;
  }
  if (c == 0) {
    cout << c << endl;
    cout << s << endl;
  } else {
    cout << c << endl;
    int k = 1;
    for (int i = 0; s[i]; i += 2) {
      if (s[i] == 'b' and s[i + 1] == 'b') s[i] = 'a';
      if (s[i] == 'a' and s[i + 1] == 'a') s[i] = 'b';
    }
    cout << s << endl;
  }
  return 0;
}
