/** gnu specific **/
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
/** contains everything I need in std **/
#include <bits/stdc++.h>

#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define sz(S) ((int)S.size())
#define FOR(i, st_, n) for(int i = st_; i < n; ++i)
#define RFOR(i, n, end_) for(int i = (n)-1; i >= end_; --i)
#define x first
#define y second
#define pb push_back
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;
typedef pair<double, double> pdd;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<ull, ull> pull;
using namespace __gnu_pbds;
typedef tree<ll, null_type, less<>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;
using namespace std;
#ifdef ONPC
mt19937 rnd(228);
#else
mt19937 rnd(chrono::high_resolution_clock::now().time_since_epoch().count());
#endif


int32_t main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    string s;
    cin >> s;
    ll n = sz(s);
    bool t = true;
    if(s[n-1] == 'E')
        t = false;
    FOR(i,1,n)
        if(s[i] == s[i-1] && s[i] == 'O')
            t = false;
    FOR(i,0,n)
        if(s[i] != 'O' && s[i] != 'E')
            t = false;
    if(!t)
    {
        cout << "INVALID" << endl;
        return 0;
    } 
    ll cur = 0;
    t = true;
    set<ll> tw;
    FOR(i,0,n)
    {
        tw.insert(pow(2ll,i));
    }
    ll res = -1;
    FOR(j,2,47)
    {
        t = true;
        cur = pow(2,j);
        RFOR(i,n,0)
        {
            if(s[i] == 'E')
                cur*=2;
            else
            {
                if((cur-1)%3 != 0)
                {
                    t = false;
                    break;
                }
                else
                    cur = (cur-1)/3;
            }
            if(tw.find(cur) != tw.end())
                t = false;
            if(cur <= 0)
                t = false;
        }
        if(t){
            if(res == -1)
                res = cur;
            else
                res = min(res,cur);
        }
    }
    if(res != -1)
        cout << res << endl;
    else
        while(true)
            res++;
}