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.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class B7 {
	private static class Node {
        int identifier;
        int value;
        Node next;
 
        public Node(int identifier, int value) {
            this.identifier = identifier;
            this.value = value;
        }
        public String toString() {
            return identifier + " " + value;
        }
    }
    private static void swap(int[] ar, int a, int b) {
        int tmp = ar[a];
        ar[a] = ar[b];
        ar[b] = tmp;
    }
    public static void main(String[] arg) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String[] nm = br.readLine().split(" ");
        int n = Integer.parseInt(nm[0]);//number of commands
        int total = Integer.parseInt(nm[1]);//total memory space
        Node head = new Node(-1, -1);
        int globalCounter = 1;//counting succesful commands
        Node freeList = new Node(-1, total);
 
        int[] ar = new int[total];
        for (int j = 0; j < n; j++) {
            String command = br.readLine();
   //if the command is "defragment"
            if (command.equals("defragment")) {
                int curIndex = 0;
                int zeroIndex = 0;
  //swapping closer to the beginning the occupied memmory              
                for (; curIndex < ar.length; ) {
                    if (ar[curIndex] != 0) {
                        swap(ar, curIndex, zeroIndex);
                        curIndex++;
                        zeroIndex++;
                    } else {
                        curIndex++;
                    }
                }
             //if the next command is "alloc"
            } else if (command.contains("alloc")) {
            //getting the size of allocated space "allocCount"
                Integer allocCount = Integer.parseInt(command.split(" ")[1]);//argument of alloc
                int index = -1;
                int count = 0;//used to compare the fitting size and the actual size needed to alloc
                for (int i = 0; i < ar.length; i++) {
      //if there is free space,argumment is added   	
                    if (ar[i] == 0) {
                        if (index == -1)
                            index = i;
                        count++;
 //if there is allocated enough memory, then the process interrupts        
                        if (count == allocCount) {
                            break;
                        }
//else if the segment isn'tt empty,starting count from 0
                    } else {
                        index = -1;
                        count = 0;
                    }
                }
//if the amount of allocated memory is too big compared to free space or doesn't fit,the NULL is displayed
                if (index == -1 || count < allocCount) {
                    System.out.println("NULL");
                    continue;
                }
//else is printed the count of current successful command                
                System.out.println(globalCounter);
//allocating memory into free space, beginning from the first empty space in array                
                for (int i = index; i < index + allocCount; i++) {
                    ar[i] = globalCounter;
                }
                globalCounter++;
            } else {
 //if the command is erase           	
                Integer index = Integer.parseInt(command.split(" ")[1]);
 //if the erase argument is a negative number,when "ILLEGAL_ERASE_ARGUMENT" is displayed               
                if (index <= 0) {
                    System.out.println("ILLEGAL_ERASE_ARGUMENT");
                    continue;
                }
                boolean found = false;
//if such argument is found in the memory space , then the erase is possible          
                for (int i = 0; i < ar.length; i++) {
                    if (ar[i] == index) {
                        found = true;
                        break;
                    }
                }
//if there is no such argument in the memory space array,when the error message is displayed                
                if (!found) {
                    System.out.println("ILLEGAL_ERASE_ARGUMENT");
                    continue;
                }
 //the proper process of erase, if in memory space array is found such argument,it is erased and replaced as 0 in array               
                for (int i = 0; i < ar.length; i++) {
                    if (ar[i] == index) {
                        ar[i] = 0;
                    }
                }
            }
        }
        br.close();
    }
 

 
    
}
