#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define MAXLEN 100

int main() {
    int C, Q;
    if (scanf("%d %d", &C, &Q) != 2 || C < 1 || Q < 1) {
        printf("Invalid input");
        return 0;
    }

    int deque = (int)malloc(C * sizeof(int));
    int front = -1, rear = -1;

    char cmd[MAXLEN];
    for (int i = 0; i < Q; i++) {
        if (scanf("%s", cmd) != 1) {
            printf("Invalid input");
            return 0;
        }

        if (strcmp(cmd, "PUSHFRONT") == 0) {
            int x;
            if (scanf("%d", &x) != 1) { printf("Invalid input"); return 0; }
            if ((front == 0 && rear == C - 1) || (rear + 1) % C == front) {
                printf("Invalid input"); return 0; // overflow
            }
            if (front == -1) {
                front = rear = 0;
            } else if (front == 0) {
                front = C - 1;
            } else {
                front--;
            }
            deque[front] = x;

        } else if (strcmp(cmd, "PUSHBACK") == 0) {
            int x;
            if (scanf("%d", &x) != 1) { printf("Invalid input"); return 0; }
            if ((front == 0 && rear == C - 1) || (rear + 1) % C == front) {
                printf("Invalid input"); return 0; // overflow
            }
            if (front == -1) {
                front = rear = 0;
            } else if (rear == C - 1) {
                rear = 0;
            } else {
                rear++;
            }
            deque[rear] = x;

        } else if (strcmp(cmd, "POPFRONT") == 0) {
            if (front == -1) {
                printf("Empty\n");
                continue;
            }
            printf("Removed\n");
            if (front == rear) {
                front = rear = -1;
            } else if (front == C - 1) {
                front = 0;
            } else {
                front++;
            }

        } else if (strcmp(cmd, "POPBACK") == 0) {
            if (front == -1) {
                printf("Empty\n");
                continue;
            }
            printf("Removed\n");
            if (front == rear) {
                front = rear = -1;
            } else if (rear == 0) {
                rear = C - 1;
            } else {
                rear--;
            }

        } else if (strcmp(cmd, "FRONT") == 0) {
            if (front == -1) printf("Empty\n");
            else printf("%d\n", deque[front]);

        } else if (strcmp(cmd, "BACK") == 0) {
            if (rear == -1) printf("Empty\n");
            else printf("%d\n", deque[rear]);

        } else if (strcmp(cmd, "ISEMPTY") == 0) {
            if (front == -1) printf("YES\n");
            else printf("NO\n");

        } else if (strcmp(cmd, "ISFULL") == 0) {
            if ((front == 0 && rear == C - 1) || (rear + 1) % C == front)
                printf("YES\n");
            else
                printf("NO\n");

        } else {
            printf("Invalid input");
            return 0;
        }
    }

    free(deque);
    return 0;
}