#include <bits/stdc++.h>
#define f(i, s, k, l) for (ll i = s; i < k; i += l)
#define for0(i, k) f(i, 0, k, 1)

#define pl pair<long long, long long>
#define pb push_back

#define vl vector<long long>
#define vi vector<int>
#define sz(x) (ll)(x).size()

using namespace std;
using ll = long long;
using ld = double;

int main() {
	ios_base::sync_with_stdio(false);
	cin.tie(nullptr);

    vector<string> s(6);
    for0(i, 6) cin >> s[i];
    swap(s[1], s.back());

    vl endsWith(26, 1e9);

    for0(i, 3 * 3 * 3 * 3 * 3 * 3 * 3 * 3) {
        char last = 'A';
        ll tmp = i;
        ll turns = 0;
        for0(d, 8) {
            if (tmp % 3 == 0 || tmp % 3 == 1) {
                if (s[tmp % 3][d] < last) turns = 1e9;
                else {
                    last = s[tmp % 3][d];
                    turns += (tmp % 3) * 2;
                    if (last == 'Q') last = 'U';
                }
            } else {
                char bestc = 'Z' + 1;
                for (ll k = 2; k < sz(s); k++) {
                    if (s[k][d] >= last) bestc = min(bestc, s[k][d] == 'Q' ? 'U' : s[k][d]);
                }
                if (bestc <= 'Z') {
                    turns++;
                    last = bestc;
                } else turns = 1e9;
            }
            tmp /= 3;
        }
        endsWith[last - 'A'] = min(endsWith[last - 'A'], turns);
    }
    for0(i, sz(endsWith) - 1) endsWith[i + 1] = min(endsWith[i], endsWith[i + 1]);

    ll res = 1e9;
    for0(i, 3 * 3 * 3 * 3 * 3 * 3 * 3 * 3) {
        char last = 'Z';
        ll tmp = i;
        ll turns = 0;
        for (ll d = 15; d >= 8; d--) {
            if (tmp % 3 == 0 || tmp % 3 == 1) {
                if ((s[tmp % 3][d] == 'Q' ? 'U' : s[tmp % 3][d]) > last) turns = 1e9;
                else {
                    last = s[tmp % 3][d];
                    turns += (tmp % 3) * 2;
                }
            } else {
                char bestc = 'A' - 1;
                for (ll k = 2; k < sz(s); k++) {
                    if ((s[k][d] == 'Q' ? 'U' : s[k][d]) <= last) bestc = max(bestc, s[k][d]);
                }
                if (bestc >= 'A') {
                    turns++;
                    last = bestc;
                } else turns = 1e9;
            }
            tmp /= 3;
        }
        res = min(res, turns + endsWith[last - 'A']);
    }
    if (res > 1000) cout << "impossible" << endl;
    else cout << res << endl;
}