3 1
erase -1
erase 0
erase -2147483648
 26 25
defragment
erase 1
erase -1560200883
alloc 44
defragment
alloc 75
alloc 22
defragment
erase 4
defragment
alloc 57
alloc 53
erase 4
erase -1639632026
erase -2121605039
erase 3
alloc 51
alloc 65
defragment
erase 2
erase 4
alloc 52
erase 3
defragment
erase -1842529282
erase 3
 12 40
erase 1
alloc 21
alloc 5
alloc 7
defragment
defragment
erase 2
alloc 83
erase 4
defragment
alloc 59
defragment
 44 46
alloc 28
alloc 36
defragment
erase -937404236
alloc 71
defragment
alloc 81
alloc 51
erase 3
defragment
alloc 48
erase 1
defragment
alloc 36
defragment
defragment
erase 1
defragment
defragment
erase -1173350787
alloc 94
erase 5
defragment
erase 9
alloc 98
erase 7
defragment
erase 5
erase 1
defragment
erase 2
defragment
erase 4
defragment
erase 9
alloc 8
defragment
erase 9
defragment
defragment
defragment
erase 1
alloc 70
erase 9
 7 6
alloc 1
alloc 2
alloc 3
erase 1
defragment
erase 3
alloc 4
 47 43
erase 1
alloc 95
alloc 53
erase 2
defragment
alloc 100
erase 4
erase 2
erase -849472053
defragment
erase -638355221
alloc 90
erase 3
erase 2
defragment
alloc 17
erase 5
defragment
erase 6
defragment
erase 3
defragment
defragment
alloc 99
alloc 69
alloc 80
erase 9
erase 5
defragment
erase 7
defragment
alloc 93
defragment
defragment
alloc 25
defragment
alloc 14
erase 8
erase 4
defragment
defragment
alloc 96
erase 9
alloc 63
erase 8
defragment
erase 10
 8 50
alloc 51
defragment
alloc 100
defragment
erase 1
alloc 50
defragment
alloc 50
 6 1
defragment
alloc 10
alloc 1
erase -1
erase 1
erase 1
 26 25
alloc 25
erase 1
alloc 24
erase 2
alloc 23
erase 3
alloc 24
erase 4
alloc 24
erase 5
alloc 21
erase 6
alloc 24
erase 7
alloc 25
erase 8
alloc 25
erase 9
alloc 24
erase 10
alloc 25
erase 11
alloc 25
erase 12
alloc 25
erase 13
 10 10
alloc 10
erase -1
erase 1
alloc 5
erase -1
alloc 5
erase 0
alloc 5
erase 0
alloc 5
 37 74
alloc 11
defragment
erase 1
defragment
erase 2
defragment
alloc 90
erase 3
erase 2
erase 3
erase 1
erase 1
alloc 38
alloc 19
erase 1
erase 3
defragment
alloc 93
erase 5
erase 4
alloc 66
alloc 71
erase 5
defragment
defragment
defragment
defragment
erase 7
alloc 47
erase -95616683
erase 2
alloc 28
alloc 32
erase 11
alloc 50
defragment
defragment
 19 46
alloc 21
erase 2
erase 1
defragment
alloc 4
defragment
defragment
alloc 40
erase 1
defragment
defragment
alloc 68
erase -388966015
alloc 85
alloc 53
erase 4
defragment
alloc 49
alloc 88
 12 10
alloc 6
alloc 2
erase 1
alloc 4
alloc 2
erase 3
alloc 2
alloc 3
alloc 1
alloc 1
alloc 1
alloc 1
 16 10
alloc 10
defragment
defragment
defragment
alloc 10
erase 1
erase 2
alloc 6
defragment
defragment
alloc 4
defragment
defragment
erase 2
defragment
alloc 6
 14 100
alloc 99
alloc 1
alloc 1
erase 2
alloc 1
erase 4
erase 1
alloc 100
alloc 1
alloc 99
defragment
erase 4
alloc 100
alloc 99
 22 9
alloc 9
erase 1
alloc 9
erase 2
alloc 9
erase 3
alloc 9
erase 4
alloc 9
erase 5
alloc 9
erase 6
alloc 9
erase 7
alloc 9
erase 8
alloc 9
erase 9
alloc 9
erase 10
alloc 9
erase 11
 42 98
defragment
defragment
defragment
defragment
defragment
alloc 5
alloc 66
defragment
erase 3
alloc 53
defragment
erase 4
erase 2
alloc 70
erase 3
defragment
defragment
erase 2
erase 3
erase -1327931832
alloc 93
alloc 64
erase 7
erase 6
erase 3
alloc 61
alloc 12
alloc 65
erase 2
alloc 46
erase 11
erase 9
erase 9
erase 6
alloc 2
alloc 78
defragment
erase 13
erase 6
erase 10
alloc 53
alloc 46
 16 10
alloc 10
defragment
defragment
defragment
alloc 10
erase 1
erase 2
alloc 6
defragment
defragment
alloc 4
defragment
defragment
erase 3
defragment
alloc 6
 38 18
alloc 72
erase 2
alloc 50
defragment
erase 3
defragment
alloc 43
alloc 41
defragment
defragment
alloc 26
alloc 46
alloc 16
alloc 15
defragment
defragment
alloc 95
erase 7
erase 7
erase 5
erase 2
erase 9
erase 7
alloc 43
defragment
erase 7
defragment
alloc 48
alloc 77
erase 10
erase 11
alloc 16
alloc 84
erase 1
defragment
alloc 86
defragment
erase 13
 16 49
erase -751005193
defragment
alloc 37
alloc 82
erase 3
erase 1
alloc 80
alloc 51
defragment
alloc 74
erase 1
alloc 91
defragment
defragment
alloc 98
defragment
 22 9
erase 1
alloc 6
alloc 65
erase 1
alloc 87
erase -1638927047
alloc 5
erase 2
alloc 70
defragment
alloc 20
alloc 48
erase -69401977
alloc 20
defragment
erase 7
defragment
erase 9
erase 7
erase 4
defragment
alloc 66
 7 100
alloc 100
erase 2147483647
erase 1
alloc 50
alloc 50
erase 3
erase -2147483648

ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
 ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
NULL
NULL
1
ILLEGAL_ERASE_ARGUMENT
NULL
NULL
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
NULL
NULL
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
NULL
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
 ILLEGAL_ERASE_ARGUMENT
1
2
3
NULL
ILLEGAL_ERASE_ARGUMENT
NULL
 1
NULL
ILLEGAL_ERASE_ARGUMENT
NULL
NULL
NULL
ILLEGAL_ERASE_ARGUMENT
NULL
2
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
NULL
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
NULL
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
3
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
NULL
ILLEGAL_ERASE_ARGUMENT
 1
2
3
4
 ILLEGAL_ERASE_ARGUMENT
NULL
NULL
ILLEGAL_ERASE_ARGUMENT
NULL
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
NULL
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
1
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
NULL
NULL
NULL
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
NULL
2
NULL
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
NULL
ILLEGAL_ERASE_ARGUMENT
NULL
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
 NULL
NULL
ILLEGAL_ERASE_ARGUMENT
1
NULL
 NULL
1
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
 1
2
3
4
5
6
7
8
9
10
11
12
13
 1
ILLEGAL_ERASE_ARGUMENT
2
ILLEGAL_ERASE_ARGUMENT
3
ILLEGAL_ERASE_ARGUMENT
NULL
ILLEGAL_ERASE_ARGUMENT
NULL
 1
ILLEGAL_ERASE_ARGUMENT
NULL
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
2
3
ILLEGAL_ERASE_ARGUMENT
NULL
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
NULL
NULL
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
NULL
ILLEGAL_ERASE_ARGUMENT
4
5
ILLEGAL_ERASE_ARGUMENT
NULL
 1
ILLEGAL_ERASE_ARGUMENT
2
3
ILLEGAL_ERASE_ARGUMENT
NULL
ILLEGAL_ERASE_ARGUMENT
NULL
NULL
ILLEGAL_ERASE_ARGUMENT
NULL
NULL
 1
2
3
4
5
NULL
6
7
8
9
 1
NULL
ILLEGAL_ERASE_ARGUMENT
2
3
4
 1
2
NULL
3
ILLEGAL_ERASE_ARGUMENT
NULL
4
NULL
NULL
NULL
 1
2
3
4
5
6
7
8
9
10
11
 1
2
ILLEGAL_ERASE_ARGUMENT
NULL
ILLEGAL_ERASE_ARGUMENT
3
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
4
NULL
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
NULL
NULL
NULL
ILLEGAL_ERASE_ARGUMENT
NULL
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
NULL
NULL
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
NULL
NULL
 1
NULL
ILLEGAL_ERASE_ARGUMENT
2
3
NULL
 NULL
ILLEGAL_ERASE_ARGUMENT
NULL
ILLEGAL_ERASE_ARGUMENT
NULL
NULL
NULL
NULL
1
NULL
NULL
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
NULL
ILLEGAL_ERASE_ARGUMENT
NULL
NULL
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
NULL
NULL
NULL
ILLEGAL_ERASE_ARGUMENT
 ILLEGAL_ERASE_ARGUMENT
1
NULL
ILLEGAL_ERASE_ARGUMENT
NULL
NULL
NULL
ILLEGAL_ERASE_ARGUMENT
NULL
NULL
 ILLEGAL_ERASE_ARGUMENT
1
NULL
NULL
ILLEGAL_ERASE_ARGUMENT
2
NULL
NULL
NULL
ILLEGAL_ERASE_ARGUMENT
NULL
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
ILLEGAL_ERASE_ARGUMENT
NULL
 1
ILLEGAL_ERASE_ARGUMENT
2
3
ILLEGAL_ERASE_ARGUMENT

import java.io.*;
import java.math.BigInteger;
import java.util.*;

public class Main
{
	private InputStream stream;
	private byte[] buf = new byte[1024];
	private int curChar;
	private int numChars;
	private SpaceCharFilter filter;
	private PrintWriter pw;
	private long mod = 1000000000 + 7;
	
	private StringBuilder ans_sb;
	private void soln()
	{	
		int m = nextInt();
		int t = nextInt();
		boolean[] arr = new boolean[t];
		int k = 1;
		HashMap<Integer,Integer> set = new HashMap<>();
		HashMap<Integer, Integer> set1 = new HashMap<>();
		TreeMap<Integer,Integer> map = new TreeMap<>();
		int mem = 0;
		for(int i=0;i<m;i++) {
			String[] s = nextLine().split(" ");
			if(s[0].charAt(0)=='a') {
				int tot = Integer.parseInt(s[1]);
				int i1 = 0;
				boolean f = false;
				for(i1=0;i1<t-tot;i1++) {
					int j1 = 0;
					for(j1 = 0; j1<tot;j1++) {
						if(arr[j1+i1])
							break;
					}
					if(j1==tot) {
						f = true;
						break;
					}
				}
				if(!f) {
					pw.println("NULL");
				}else {
					pw.println(k++);
					set.put(k-1,i1);
					set1.put(k-1, tot);
					map.put(i1, k-1);
					for(int j1=0;j1<tot;j1++)
						arr[i1+j1] = true;
				}
			}else if(s[0].charAt(0)=='e') {
				int num = Integer.parseInt(s[1]);
				if(set.containsKey(num)) {
					int i1 = set.get(num);
					int tot = set1.get(num);
					set.remove(num);
					set1.remove(num);
					map.remove(i1);
					for(int j1=0;j1<tot;j1++)
						arr[i1+j1] = false;
				}else {
					pw.println("ILLEGAL_ERASE_ARGUMENT");
				}
			}else {
				Arrays.fill(arr,false);
				int st = 0;
				for(int i1:map.keySet()) {
					int key = map.get(i1);
					int tot = set1.get(key);
					set.put(key, st);
					st += tot;
				}
				for(int j1=0;j1<st;j1++)
					arr[j1] = true;
				map.clear();
				for(int key:set.keySet()) {
					int sta = set.get(key);
					map.put(sta, key);
				}
				//debug(map);
			}
			
		}
	}
	private class Node implements Comparable<Node>{
		int node;
		int dist;

		@Override
		public int compareTo(Node arg0)
		{
			if(this.dist != arg0.dist)
				return (int) (this.dist - arg0.dist);
			return this.node - arg0.node;
		}
		public boolean equals(Object o){
			if(o instanceof Node){
				Node c = (Node)o;
				return this.node == c.node && this.dist == c.dist;
			}
			return false;
		}
		public String toString() {
			return this.node+", "+this.dist;
		}
	}
	
	private void debug(Object... o) {
		System.out.println(Arrays.deepToString(o));
	}
	
	private long pow(long a, long b, long c)
	{
		if (b == 0)
			return 1;
		long p = pow(a, b / 2, c);
		p = (p * p) % c;
		return (b % 2 == 0) ? p : (a * p) % c;
	}

	private long gcd(long n, long l)
	{
		if (l == 0)
			return n;
		return gcd(l, n % l);
	}
	public static void main(String[] args) throws Exception
	{
		new Thread(null, new Runnable()
		{
			@Override
			public void run()
			{
				new Main().solve();
			}
		}, "1", 1 << 26).start();
	}
	public StringBuilder solve(){
		InputReader(System.in);
		/*try { 
			InputReader(new FileInputStream("C:\\Users\\hardik\\Desktop\\in.txt"));
		} catch(FileNotFoundException e) {}
		*/
		pw = new PrintWriter(System.out);
		ans_sb = new StringBuilder();
		soln();
		
		pw.close();
		//System.out.println(ans_sb);
		return ans_sb;
	}
	public void InputReader(InputStream stream1)
	{
		stream = stream1;
	}

	private boolean isWhitespace(int c)
	{
		return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
	}

	private boolean isEndOfLine(int c)
	{
		return c == '\n' || c == '\r' || c == -1;
	}

	private int read()
	{
		if (numChars == -1)
			throw new InputMismatchException();
		if (curChar >= numChars)
		{
			curChar = 0;
			try
			{
				numChars = stream.read(buf);
			} catch (IOException e)
			{
				throw new InputMismatchException();
			}
			if (numChars <= 0)
				return -1;
		}
		return buf[curChar++];
	}

	private int nextInt()
	{
		int c = read();
		while (isSpaceChar(c))
			c = read();
		int sgn = 1;
		if (c == '-')
		{
			sgn = -1;
			c = read();
		}
		int res = 0;
		do
		{
			if (c < '0' || c > '9')
				throw new InputMismatchException();
			res *= 10;
			res += c - '0';
			c = read();
		} while (!isSpaceChar(c));
		return res * sgn;
	}

	private long nextLong()
	{
		int c = read();
		while (isSpaceChar(c))
			c = read();
		int sgn = 1;
		if (c == '-')
		{
			sgn = -1;
			c = read();
		}
		long res = 0;
		do
		{
			if (c < '0' || c > '9')
				throw new InputMismatchException();
			res *= 10;
			res += c - '0';
			c = read();
		} while (!isSpaceChar(c));
		return res * sgn;
	}

	private String nextToken()
	{
		int c = read();
		while (isSpaceChar(c))
			c = read();
		StringBuilder res = new StringBuilder();
		do
		{
			res.appendCodePoint(c);
			c = read();
		} while (!isSpaceChar(c));
		return res.toString();
	}

	private String nextLine()
	{
		int c = read();
		while (isSpaceChar(c))
			c = read();
		StringBuilder res = new StringBuilder();
		do
		{
			res.appendCodePoint(c);
			c = read();
		} while (!isEndOfLine(c));
		return res.toString();
	}

	private int[] nextIntArray(int n)
	{
		int[] arr = new int[n];
		for (int i = 0; i < n; i++)
		{
			arr[i] = nextInt();
		}
		return arr;
	}

	private long[] nextLongArray(int n)
	{
		long[] arr = new long[n];
		for (int i = 0; i < n; i++)
		{
			arr[i] = nextLong();
		}
		return arr;
	}

	private void pArray(int[] arr)
	{
		for (int i = 0; i < arr.length; i++)
		{
			System.out.print(arr[i] + " ");
		}
		System.out.println();
		return;
	}

	private void pArray(long[] arr)
	{
		for (int i = 0; i < arr.length; i++)
		{
			System.out.print(arr[i] + " ");
		}
		System.out.println();
		return;
	}

	private boolean isSpaceChar(int c)
	{
		if (filter != null)
			return filter.isSpaceChar(c);
		return isWhitespace(c);
	}

	private char nextChar()
	{
		int c = read();
		while (isSpaceChar(c))
			c = read();
		char c1 = (char) c;
		while (!isSpaceChar(c))
			c = read();
		return c1;
	}

	private interface SpaceCharFilter
	{
		public boolean isSpaceChar(int ch);
	}
}