#include<bits/stdc++.h>
using namespace std;
stack<int> aaa,bbb,ccc;
struct hhh{
	int aa,bb;
}a[40000005];
int n,e[40000005],f,g=0,ab[100000005],ac[100000005],bc[100000005],ba[100000005],zz1=1,jl=1;
int main(){
	ios::sync_with_stdio(0);
	cin>>n;
	for(int i=1;i<=n;i++){
		cin>>e[i];
	}
	for(int i=n;i>0;i--){
		aaa.push(e[i]);
		a[e[i]].bb=1;
	}
	for(int i=n;i>0;i--){
		if(a[i].bb==1){
			for(int j=0;j<=aaa.size();j++){
				f=aaa.top();
				if(f!=i){
					bbb.push(f);
					aaa.pop();
					ab[zz1]++;
					g++;
					a[f].bb=2;
				}
				else break;
			}
			aaa.pop();
			if(ab[zz1]!=0) zz1++;
			ac[zz1]++;
			zz1++;
			g++;
		}
		else{
			for(int j=0;j<=bbb.size();j++){
				f=bbb.top();
				if(f!=i){
					aaa.push(f);
					bbb.pop();
					ba[zz1]++;
					g++;
					a[f].bb=1;
				}
				else break;
			}
			bbb.pop();
			if(ba[zz1]!=0) 	zz1++;
			bc[zz1]++;
			zz1++;
			g++;
		}
	}
	cout<<g<<endl;
	for(int i=1;i<=zz1;i++){
		for(int j=1;j<=ab[i];j++){
			cout<<"A B"<<endl;
		}
		for(int j=1;j<=ac[i];j++){
			cout<<"A C"<<endl;
		}
		for(int j=1;j<=bc[i];j++){
			cout<<"B C"<<endl;
		}
		for(int j=1;j<=ba[i];j++){
			cout<<"B A"<<endl;
		}
	}
	return 0;
}