#include <bits/stdc++.h>
// #include <ext/pb_ds/assoc_container.hpp> 
// #include <ext/pb_ds/tree_policy.hpp>
 
using namespace std;
// using namespace __gnu_pbds;
typedef long long ll;
typedef long double ld;
 
typedef pair<ll, ll> pl;
typedef pair<ld,ld> pd;
typedef vector<ll> vl;
// typedef tree<ll, null_type, less<ll>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;
 
 
#define G(x) ll x; cin >> x;
#define F(i, l, r) for (ll i = l; i < (r); ++i)
#define all(a) begin(a), end(a)
#define K first
#define V second
#define OK(i,j) i >= 0 && i < n && j >= 0 && j < m
 
#define NN 2000005
#define MM 5005
#define MOD 1000000007

void solve() {
 
    string s;
    cin >> s;
    ll n = s.length();
    bool ok = 1;
    for(ll i=0;i<n;i++) {
        if(s[i] != 'E' && s[i] != 'O') ok = 0;
    }

    if(s[n-1] != 'O') ok = 0;

    for(ll i=1;i<n;i++) {
        if(s[i] == 'O' && s[i-1] == 'O') ok = 0;
    }

    if(!ok) {
        cout << "INVALID\n";
        return;
    }

    ll ans = 1e18;
    ll num = 8;
    for(ll c=3;c<=63;c++) {
        ll k = num;
        ok = 1;
        for(ll i=n-1;i>=0;i--) {
            if(s[i] == 'O') {
                if((k-1)%3 != 0) ok = 0;
                else k = (k-1)/3;
            }
            else k = 2*k;
            if(k < 0) ok = 0;
        }
        if(ok) ans = min(ans,k);
        num *= 2;
    }

    if(ans > pow(2,47)) cout << "INVALID\n";
    else cout << ans << '\n';
    return;
}

int main() {
    cin.tie(0)->sync_with_stdio(0);
    cout << fixed << setprecision(10);

    // G(t);
    // while(t--)
        solve();

    return 0;

}