#include <bits/stdc++.h>
using namespace std;
const int MAXN = 200010;
char str[MAXN];
int main() {
  int n;
  scanf("%d", &n);
  scanf("%s", str);
  int cnt = 0;
  for (int i = 0; i < n; i += 2) {
    if (str[i] == 'a' && str[i + 1] == 'a') {
      cnt++;
      str[i] = 'b';
    } else if (str[i] == 'b' && str[i + 1] == 'b') {
      cnt++;
      str[i] = 'a';
    }
  }
  printf("%d\n", cnt);
  printf("%s\n", str);
  return 0;
}
