#include <bits/stdc++.h>
using namespace std;
typedef signed long long ll;

#define _P(...) (void)printf(__VA_ARGS__)
#define FOR(x,to) for(x=0;x<(to);x++)
#define FORR(x,arr) for(auto& x:arr)
#define FORR2(x,y,arr) for(auto& [x,y]:arr)
#define ALL(a) (a.begin()),(a.end())
#define ZERO(a) memset(a,0,sizeof(a))
#define MINUS(a) memset(a,0xff,sizeof(a))
template<class T> bool chmax(T &a, const T &b) { if(a<b){a=b;return 1;}return 0;}
template<class T> bool chmin(T &a, const T &b) { if(a>b){a=b;return 1;}return 0;}
//-------------------------------------------------------

int N,K;
string P;
set<int> E[20220];

vector<vector<int>> build_prufer(vector<int> V) {
	int N=V.size()+2;
	vector<int> D;
	vector<vector<int>> E;
	int i,x,y;
	FOR(i,N) D.push_back(1);
	E.resize(N);
	FORR(v,V) D[v]++;
	set<int> cand;
	FOR(i,N) if(D[i]==1) cand.insert(i);
	FORR(v,V) {
		x=*cand.begin();
		cand.erase(x);
		E[v].push_back(x);
		E[x].push_back(v);
		D[v]--;
		D[x]--;
		if(D[v]==1) cand.insert(v);
		if(D[x]==1) cand.insert(x);
	}
	x=y=-1;
	FOR(i,N) if(D[i]==1) {
		if(x==-1) x=i;
		else y=i;
	}
	E[x].push_back(y);
	E[y].push_back(x);
	return E;
}

void solve() {
	int i,j,k,l,r,x,y; string s;
	
	cin>>P;
	if(P=="Alice") {
		cin>>N;
		cout<<N-2<<endl;
		FOR(i,N-1) {
			cin>>x>>y;
			E[x-1].insert(y-1);
			E[y-1].insert(x-1);
		}
		FOR(i,N-2) {
			FOR(j,N) if(E[j].size()==1) break;
			x=*E[j].begin();
			cout<<x+1<<" ";
			E[x].erase(j);
			E[j].clear();
		}
		cout<<endl;
	}
	else {
		cin>>N;
		cout<<N-2<<endl;
		vector<int> V;
		FOR(i,N-2) {
			cin>>x;
			V.push_back(x-1);
		}
		auto E=build_prufer(V);
		FOR(i,N) FORR(e,E[i]) if(i<e) cout<<i+1<<" "<<e+1<<endl;
	}
}


int main(int argc,char** argv){
	string s;int i;
	if(argc==1) ios::sync_with_stdio(false), cin.tie(0);
	FOR(i,argc-1) s+=argv[i+1],s+='\n'; FOR(i,s.size()) ungetc(s[s.size()-1-i],stdin);
	cout.tie(0); solve(); return 0;
}