#include<bits/stdc++.h>
using namespace std;

typedef long long ll;

void print(__int128 x) {
    if (x > 9) print(x / 10);
    putchar(x % 10 + '0');
}

__int128 read() {
    __int128 x = 0;
    string s; cin >> s;
    reverse(s.begin(), s.end());
    while (s.size()) {
        x = x * 10 + s.back() - '0';
        s.pop_back();
    }
    return x;
}

bool test(__int128 x) {
    while (x % 2 == 0) x /= 2;
    return x == 1;
}

signed main() {
    // cin.tie(0)->sync_with_stdio(0);
    if (fopen("qoj_7692.inp", "r")) {
        freopen("qoj_7692.inp", "r", stdin);
        freopen("qoj_7692.out", "w", stdout);
    }

    #ifdef LOCAL_MACHINE 
        if (fopen("task.inp", "r")) {
            freopen("task.inp", "r", stdin);
            freopen("task.out", "w", stdout);
        }
    #endif

    string s; cin >> s;
    for (int i = 0; i + 1 < s.size(); ++i) if (s[i] == 'O' && s[i + 1] == 'O') {
        cout << "INVALID\n";
        exit(0);
    }
    if (s.back() == 'E') {
        cout << "INVALID\n";
        exit(0);
    }

    int ce = 0;
    for (int i : s) ce += i == 'E';

    unsigned __int128 ans = 0; 
    ans -= 1;

    for (int ed = 2; ed < 128 - ce; ++ed) {
        __int128 x = 1;
        for (int i = 0; i < ed; ++i) x *= 2;

        bool ok = 1;
        for (int i = (int)s.size() - 1; ~i; --i) {
            if (s[i] == 'O') {
                x -= 1;
                if (x % 3 != 0) {
                    ok = 0;
                    break;
                }
                x /= 3;
                if (x % 2 == 0) {
                    ok = 0;
                    break;
                }
            }
            else x *= 2;

            if (test(x)) {
                ok = 0;
                break;
            }
        }

        if (ok && ans > x) ans = x;
    }

    print(ans);
}

// ඞඞඞඞඞ you sus