#include <bits/stdc++.h>
using namespace std;

#define rep(i,a,b) for (int i = (a); i < (b);++i)
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
#define fo(i, n) for(int i=0;i<(n);i++)
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;

const int NMAX = 2123;
char a[NMAX];
char b[NMAX];

#define OUT(a...) {char outs[100]; sprintf(outs, a); out.push_back(outs);}

map<pair<int, int>, vector<int>> s;

int ps(char x){ return x=='M'?-1:x=='C'?1:0;}

int get(vector<int> &vec){int r = vec[vec.size()-1]; vec.pop_back(); return r;}
signed main() {
	int n;
	int cur;
	int on_board=0;
	scanf("%d %s %s", &n, a, b);
	fo(i,n)
	{
		s[{ps(b[i]), ps(a[i])}].push_back(i+1);
	}

	for(int startm=-1; startm <= 2; startm+=2){
		vector<string> out;
		if(!s[{startm, 0}].size()) goto next;
		OUT("DRIVE %d", cur=get(s[{startm, 0}]));
		OUT("PICKUP");
		on_board=startm;
		while(s[{-on_board, on_board}].size())
		{

			OUT("DRIVE %d", cur=get(s[{-on_board, on_board}]));
			OUT("DROPOFF");
			OUT("PICKUP");
			on_board = -on_board;
		}
		if(s[{0, on_board}].size())
		{
			OUT("DRIVE %d", cur=get(s[{0, on_board}]));
			OUT("DROPOFF");
		}
		else out.pop_back();
		on_board = 0;


		for(int x=-1; x <= 2; x+=2){
			while(s[{-x, x}].size())
			{
				if(!s[{x, 0}].size()) goto next;
				OUT("DRIVE %d", cur=get(s[{x, 0}]));
				OUT("PICKUP");
				OUT("DRIVE %d", cur=get(s[{-x, x}]));
				OUT("DROPOFF");
				OUT("PICKUP");
				if(s[{0, -x}].size())
				{
					OUT("DRIVE %d", cur=get(s[{0, -x}]));
					OUT("DROPOFF");
				}
				else out.pop_back();
			}
		}
		for(int x=-1; x <= 2; x+=2){
			while(s[{0, x}].size())
			{
				if(!s[{x, 0}].size()) goto next;
				OUT("DRIVE %d", cur=get(s[{x, 0}]));
				OUT("PICKUP");
				OUT("DRIVE %d", cur=get(s[{0, x}]));
				OUT("DROPOFF");
			}
		}

		printf("%d\n", int(out.size()));
		for(string s: out) printf("%s\n", s.c_str());
	return 0;

next:;
	}
	printf("%d\n", 0);
	return 0;
}