//#define NOSTDCPP
//#define Cpp11
//#define Linux_System
#ifndef NOSTDCPP
	
#include <bits/stdc++.h>
	
#else
	
#include <algorithm>
#include <bitset>
#include <cassert>
#include <climits>
#include <complex>
#include <cstring>
#include <cstdio>
#include <deque>
#include <exception>
#include <functional>
#include <iomanip>
#include <iostream>
#include <istream>
#include <iterator>
#include <list>
#include <map>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <typeinfo>
#include <utility>
#include <valarray>
#include <vector>
	
#endif
	
# ifdef Linux_System
# define getchar getchar_unlocked
# define putchar putchar_unlocked
# endif
	
# define RESET(_) memset(_, 0, sizeof(_))
# define RESET_(_, val) memset(_, val, sizeof(_))
# define fi first
# define se second
# define pb push_back
# define midf(x, y) ((x + y) >> 1)
# define DXA(_) ((_ << 1))
# define DXB(_) ((_ << 1) | 1)
	
# define next __Chtholly__
# define x1 __Mercury__
# define y1 __bbtl04__
# define index __ikooo__
	
using namespace std;
	
typedef long long ll;
typedef unsigned long long ull;
typedef vector <int> vi;
typedef set <int> si;
typedef pair <int, int> pii;
typedef long double ld;
	
const int MOD = 1e9 + 7;
const int maxn = 1000009;
const int maxm = 300009;
const ll inf = 1e18;
const double pi = acos(-1.0);
const double eps = 1e-6;
	
ll myrand(ll mod){return ((ll)rand() << 32 ^ (ll)rand() << 16 ^ rand()) % mod;}
	
template <class T>
inline bool scan_d(T & ret)
{
	char c;
	int sgn;
	if(c = getchar(), c == EOF)return false;
	while(c != '-' && (c < '0' || c > '9'))c = getchar();
	sgn = (c == '-') ? -1 : 1;
	ret = (c == '-') ? 0 : (c - '0');
	while(c = getchar(), c >= '0' && c <= '9')
		ret = ret * 10 + (c - '0');
	ret *= sgn;
	return true;
}
#ifdef Cpp11
template <class T, class ... Args>
inline bool scan_d(T & ret, Args & ... args)
{
	scan_d(ret);
	scan_d(args...);
}
#define cin.tie(0); cin.tie(nullptr);
#define cout.tie(0); cout.tie(nullptr);
#endif
inline bool scan_ch(char &ch)
{
	if(ch = getchar(), ch == EOF)return false;
	while(ch == ' ' || ch == '\n')ch = getchar();
	return true;
}
	
template <class T>
inline void out_number(T x)
{
	if(x < 0)
	{
		putchar('-');
		out_number(- x);
		return ;
	}
	if(x > 9)out_number(x / 10);
	putchar(x % 10 + '0');
}
	
struct knowledge
{
	int val, next;
}know[maxn];
	
struct student
{
	int fir, forget;
}student[maxn];
	
int q, m, n, now, x, y;
char type[20];
	
inline void learn(int x, int y)
{
	know[++ now].val = y;
	know[now].next = student[x].fir;
	student[x].fir = now;
}
	
inline void rollback(int x)
{
	int p = student[x].fir;
	know[++ now].val = know[p].val;
	student[x].fir = know[p].next;
	know[now].next = student[x].forget;
	student[x].forget = now;
}
	
inline void relearn(int x)
{
	int p = student[x].forget;
	know[++ now].val = know[p].val;
	student[x].forget = know[p].next;
	know[now].next = student[x].fir;
	student[x].fir = now;
}
	
inline void clone(int x)
{
	++ n;
	student[n] = student[x];
}
	
inline int check(int x)
{
	return ! student[x].fir ? -1 : know[student[x].fir].val;
}
	
int main()
{
	scanf("%d %d", &q, &m);
	n = now = 1;
	RESET(student);
	RESET(know);
	while(q --)
	{
		scanf(" %s", type);
		switch(type[3])
		{
			case 'r': //learn
				scanf("%d %d", &x, &y);
				learn(x, y);
				break;
			case 'l': //rollback
				scanf("%d", &x);
				rollback(x);
				break;
			case 'e': //relearn
				scanf("%d", &x);
				relearn(x);
				break;
			case 'n': //clone
				scanf("%d", &x);
				clone(x);
				break;
			case 'c': //check
				scanf("%d", &x);
				if((y = check(x)) == -1) puts("basic");
				else printf("%d\n", y);
				break;
			default:
				puts(type);
				assert(false);
		}
	}
	return 0;
}
	
/*
9 10
learn 1 5
learn 1 7
rollback 1
check 1
clone 1
relearn 2
check 2
rollback 1
check 1
*/
	
/*
14 10
learn 1 1
learn 1 3
rollback 1
rollback 1
clone 1
learn 1 2
relearn 2
check 2
relearn 2
check 2
rollback 2
check 2
rollback 2
check 2
*/