#include <stdio.h>

#define MAX_N 300010
#define inf (int)(1e9)

int st[MAX_N], man[MAX_N], vl[MAX_N], vr[MAX_N], n, tmp[MAX_N], cmx[MAX_N];

int max(int a, int b) { return a < b ? b : a; }
int min(int a, int b) { return a < b ? a : b; }

void swap(int *a, int *b) {
    int c = *b;
    *b = *a, *a = c;
}

void reverse(int *l, int *r) {
    while (l < r) swap(l, r-1), ++l, --r;
}

void getv(int v[]) {
    int m = 0;
    tmp[m++] = -1;
    for (int i = 0;i < n;++i)
        tmp[m++] = st[i], tmp[m++] = -1;

    // manacher
    for (int l = -1, r = -1, i = 0;i < m;++i) {
        man[i] = 1;
        if (r >= i) man[i] = min(r - i + 1, man[l + r - i]);
        while (i + man[i] < m && i - man[i] >= 0 && tmp[i-man[i]] == tmp[i+man[i]])
            ++man[i];
        if (i + man[i] - 1 >= r)
            l = i - man[i] + 1, r = i + man[i] - 1;
    }

    for (int i = 0;i < m;++i) cmx[i] = 0;

    for (int i = 0;i < m;++i) {
        int l = i - man[i] + 1, wid = man[i] * 2 - 1;
        cmx[l] = max(cmx[l], wid);
    }
    for (int i = 1;i < m;++i)
        cmx[i] = max(cmx[i], cmx[i-1] - 2);

    for (int i = 0;i < m;++i) {
        int l = i/2, wid = (cmx[i]-1)/2;
        v[l] = max(v[l], wid);
    }
}

int main() {
    while (scanf("%d", st+n) != EOF) ++n;

    getv(vl);
    reverse(st, st+n);
    getv(vr);
    reverse(st, st+n);
    reverse(vr, vr+n);

    int res = 0, beg = 0;
    for (int i = 1;i < n;++i) {
        if (vl[i] + vr[i-1] > res || vl[i]+vr[i-1]==res && i-vr[i-1]>beg)
            res = vl[i] + vr[i-1], beg = i - vr[i-1];
    }

    for (int i = 0;i < res;++i) {
        printf("%d", st[i+beg]);
        if (i+1 < res) printf(" ");
    }
    puts("");
}