#include <bits/stdc++.h>
using namespace std;
const int INF = 0x3f3f3f3f;
const int MOD = 1e9 + 7;
const int MX = 2e5 + 7;
char str[MX];
int main() {
  int n;
  while (cin >> n >> str) {
    int a = 0, b = 0;
    int al = -1, bl = -1;
    int ans = 0;
    for (int i = 1; i < n; i += 2) {
      if (str[i - 1] == str[i]) {
        ans++;
        if (str[i] == 'a')
          str[i] = 'b';
        else
          str[i] = 'a';
      }
    }
    cout << ans << endl;
    cout << str << endl;
  }
  return 0;
}
