#include <stdio.h>

void moving(char a,char b)
{
    printf("%c->%c\n",a,b);
}
void han(int n,char a,char b,char c)
{
    if(n>0)
    {
        han(n-1,a,c,b);
        moving(a,b);
        han(n-1,c,b,a);
    }
}
int main()
{
    int n;
    scanf("%d",&n);
    printf("%d\n",(1<<n)-1);
    han(n,'A','B','C');
    return0;
}