int f(char *s)
{
  int m = 0, c = 0;
  while (*s) {
    c++;
    if (*s != *(s + 1)) {
      if (c > m)
        m = c;
      c = 0;
    }
    s++;
  }
  return m;
}

int main()
{
  char *s = "aaaaaaaaabbbbbbbbbbbbbaaaagggdfaaaaaaaaaaarwetrwe";
  int r = f(s);
}