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

typedef struct {
    int index, value;
} Pair;

int comparator(const void* a, const void* b) {
    Pair* A = (Pair*)a;
    Pair* B = (Pair*)b;

    if(A->value == B->value) return A->index - B->index;
    return B->value - A->value;
}

int main() {
    int N;
    scanf("%d",&N);
    Pair* pair_A = (Pair*)malloc(sizeof(Pair)*N);

    for(int i=0; i<N; i++) {
        int value;
        scanf("%d",&value);
        Pair temp = {i, value};
        pair_A[i] = temp;
    }

    qsort(pair_A, N, sizeof(Pair),comparator);

    int M;
    scanf("%d",&M);
    Pair* pair_B = (Pair*)malloc(sizeof(Pair)*M);

    for(int i=0; i<M; i++) {
        int value;
        scanf("%d",&value);
        Pair temp = {i, value};
        pair_B[i] = temp;
    }

    qsort(pair_B, M, sizeof(Pair), comparator);

    int idxA = 0, idxB = 0;
    int limitA = -1, limitB = -1;
    int* subsequence = (int*)malloc(sizeof(int)*(M > N ? M : N));
    int size = 0;

    while(idxA < N && idxB < M) {
        int posA = pair_A[idxA].index, valA = pair_A[idxA].value;
        int posB = pair_B[idxB].index, valB = pair_B[idxB].value;

        if(valA == valB) {
            if(posA > limitA && posB > limitB) {
                subsequence[size++] = valA;
                idxA++; idxB++;
                limitA = posA;
                limitB = posB;
            }
            else if(posA <= limitA) idxA++;
            else idxB++;
        }
        else if(valA > valB) idxA++;
        else idxB++;
    }

    printf("%d\n",size);
    for(int i=0; i<size; i++) printf("%d ",subsequence[i]);
    printf("\n");

    free(pair_A);
    free(pair_B);
    free(subsequence);

    return 0;
}