#include <bits/stdc++.h>

using LL = long long;

FILE *fin, *fout, *ferr;

std::mt19937 gen(1919810);

static const int N = 100'005;

int n;
LL a[N];
std::map<LL, int> map;
char opt[N];

signed main()
{
    std::uniform_int_distribution<LL> random(1, 1LL << 62);
    fin = stdin, fout = stdout, ferr = stderr;
    fscanf(fin, "%s", opt + 1);
    LL tmp = 0;
    if (opt[1] == 'r')
        fscanf(fin, "%lld", &tmp);
    fscanf(fin, "%d", &n);
    for (int i = 1; i < N; ++i)
        a[i] = random(gen), map[a[i]] = i;
    for (int i = 1; i <= n; ++i)
    {
        static int x;
        fscanf(fin, "%d", &x);
        tmp ^= a[x];
        if (tmp == 0)
            fprintf(fout, "%d\n", 0);
        else if (map.count(tmp))
            fprintf(fout, "%d\n", map[tmp]);
        else
            fprintf(fout, "%d\n", -1);
    }
    if (opt[1] == 's')
        fprintf(fout, "%lld\n", tmp);
    return 0;
}