/*

Author: Haze

2024/5/23

*/

#include <bits/stdc++.h>

#include <ranges>

#define irep(i, l, r) for(int i = (l); i <= (r); ++ i)
#define drep(i, r, l) for(int i = (r); i >= (l); -- i)
#define IOS ios::sync_with_stdio(false), cin.tie(nullptr);
using namespace std;
typedef __int128 ll;

inline __int128 read() {
    __int128 s = 0;
    bool fl = false;
    char ch = (char) getchar();
    while (!isdigit(ch)) {
        if (ch == '-')fl = true;
        ch = (char) getchar();
    }
    while (isdigit(ch)) {
        s = s * 10 + (ch ^ 48);
        ch = (char) getchar();
    }
    return fl ? -s : s;
}

void print(__int128 S){
    if(S){
        print(S / 10);
        cout << (int)(S % 10);
    }
}

const int mod = 1000000000 + 7;
const int itinf = 1000000999;
const ll llinf = 2e18;
const int N = 500099;

void solve() {
    string s;
    cin >> s;
    if(s.back() == 'E' or count(s.begin(), s.end(), 'O') + count(s.begin(), s.end(), 'E') != s.length()){
        cout << "INVALID";
        return;
    }

    ll ans = (ll)(1) << 126;
//    print(ans);
    int n = s.length();
    irep(i, 0, n - 2){
        if(s[i] == 'O' and s[i + 1] == 'O'){
            cout << "INVALID";
            return;
        }
    }


    ll inf = (ll)(1) << 49;
    for(ll x = 1; x <= inf; x *= 2){
        if(x == inf)break;
        int ok = 1;
        ll t = x;
        for(char & it : ranges::reverse_view(s)){
            if(it == 'O'){
                if((t - 1) % 3 == 0 && ((t - 1) / 3) % 2 == 1)t = (t - 1) / 3;
                else{
                    ok = 0;
                    break;
                }
            }
            else{
                t *= 2;
            }
        }
        if(ok and t != (t & -t))ans = min(ans, t);
    }
    if(ans == (ll)(1) << 126)cout << "INVALID";
    else print(ans);
}

int main() {
    // IOS
    ll x = 126;
//    print((ll)(1) << x);
    int T = 1;
    while (T--) {
        solve();
    }
    return 0;
}