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

const int STACK_MIN_SIZE = 1024;

typedef struct {
    int length;
    int index;
    void *buffer;
    size_t size;
} stack;

stack *create_stack(size_t size) {
    stack *new = malloc(sizeof(stack));
    new->length = STACK_MIN_SIZE;
    new->index = -1;
    new->buffer = malloc(size * new->length);
    new->size = size;
    return new;
}

void delete_stack(stack *s) {
    free(s->buffer);
    free(s);
}

void expand(stack *s) {
    s->length *= 2;
    s->buffer = realloc(s->buffer, s->length);
    if (!s->buffer) {
        fprintf(stderr, "Reallocating memory failed\n");
        exit(1);
    }
}

void push(stack *s, void *element) {
    if (s->length <= ++s->index)
        expand(s);

    memcpy(s->buffer + s->index * s->size, element, s->size);
}

int pop(stack *s, void *buf) {
    if (s->index < 0)
        return 0;

    memcpy(buf, s->buffer + s->index * s->size, s->size);
    s->index--;
    return 1;
}

const char IN_FILE[] = "stack.in";
const char OUT_FILE[] = "stack.out";

int main() {
    stack *ints = create_stack(sizeof(int));
    FILE *in = fopen(IN_FILE, "r"),
         *out = fopen(OUT_FILE, "w");
    /* this works though
    stack *ints = malloc(sizeof(stack));
    ints->buffer = malloc(100000 * sizeof(int));
    ints->index = -1;
    ints->length = 100000;
    ints->size = sizeof(int); */
    int n, x;
    char op;
    fscanf(in, "%d", &n);
    for (int i = 0; i < n; ++i) {
        fscanf(in, "\n%c", &op);
        switch(op) {
            case '+':
                fscanf(in, "%d", &x);
                push(ints, &x);
                break;
            case '-':
                pop(ints, &x);
                fprintf(out, "%d\n", x);
        }
    }
}