#include <bits/stdc++.h>
using namespace std;
const int MAXN = 1e6;
int n, sum;
char s[MAXN];
int main() {
  scanf("%d", &n);
  scanf("%s", s + 1);
  for (int i = 1; i <= n; i += 2) {
    if ((s[i] == 'a' && s[i + 1] == 'a') || (s[i] == 'b' && s[i + 1] == 'b')) {
      sum++;
      if (s[i] == 'a')
        s[i] = 'b';
      else
        s[i] = 'a';
    }
  }
  printf("%d\n", sum);
  printf("%s", s + 1);
  return 0;
}
