#include <bits/stdc++.h>
int n, i, cnt;
char s[1000000];
int main() {
  scanf("%d", &n);
  scanf("%s", s);
  cnt = 0;
  for (i = 0; i < n; i = i + 2) {
    if (s[i] == s[i + 1] && s[i] == 'a') {
      s[i] = 'b';
      cnt++;
    } else if (s[i] == s[i + 1] && s[i] == 'b') {
      s[i] = 'a';
      cnt++;
    }
  }
  printf("%d\n", cnt);
  printf("%s", s);
}
