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

#define CAPACITY 101 // 100 changes max; so (rear + 1) % 101 for wrap

int main() {
    int n;
    if (scanf("%d", &n) != 1 || n < 1 || n > 100) {
        printf("Invalid input");
        return 0;
    }

    int chain[CAPACITY];
    int rear = -1; // Initially empty

    for (int i = 0; i < n; i++) {
        char input[2];
        if (scanf("%s", input) != 1) {
            printf("Invalid input");
            return 0;
        }

        if (input == '-') {
            if (rear == -1) {
                printf("the chain was empty\n");
            } else {
                int color = chain;
                printf("%d\n", color);
                // Shift all lanterns left (removes first one)
                for (int j = 0; j < rear; j++) {
                    chain[j] = chain[j + 1];
                }
                rear = (rear == 0) ? -1 : rear - 1;
            }
        } else {
            int color = atoi(input);
            if (color < 1 || color > 1000) {
                printf("Invalid input");
                return 0;
            }
            // Add at the end using modular capacity
            rear = (rear + 1) % CAPACITY;
            chain[rear] = color;
        }
    }
    return 0;
}