#pragma GCC optimize("O3,unroll-loops")
#include <bits/stdc++.h>
using namespace std;

#ifdef WAIMAI
#define debug(HEHE...) cout << "[" << #HEHE << "] : ", dout(HEHE)
void dout() {cout << '\n';}
template<typename T, typename...U>
void dout (T t, U...u) {cout << t << (sizeof... (u) ? ", " : ""), dout (u...);}
#else
#define debug(...) 7122
#endif

#define ll long long
#define Waimai ios::sync_with_stdio(false), cin.tie(0)
#define FOR(x,a,b) for (int x = a, I = b; x <= I; x++)
#define pb emplace_back
#define F first
#define S second

#define int long long
#define bigint __int128

const int INF = 1e18;
const int lim = 1ll << 47;

int n, ans;
string s;

bool istwo(bigint x) {
    bigint y = 1;
    while (y < x) y *= 2;
    return x == y;
}
int cal(bigint x) {
    for (int i = n; i >= 1; i--) {
        if (s[i] == 'O') {
            if ((x - 1) % 3 != 0) return INF;
            x--, x /= 3;
            if (x % 2 == 0) return INF;
        } else {
            x *= 2;
        }
        if (istwo(x)) return INF;
    }
    if (x > lim) return INF;
    return (int) x;
}

void solve() {
    cin >> s;
    n = s.size(), s = " " + s;
    if (s[n] != 'O') {
        cout << "INVALID\n";
        return;
    }
    FOR (i, 1, n - 1) if (s[i] == 'O' && s[i + 1] == 'O') {
        cout << "INVALID\n";
        return;
    }
    FOR (i, 1, n) if (s[i] != 'E' && s[i] != 'O') {
        cout << "INVALID\n";
        return;
    }
    ans = INF;
    bigint x = 1;
    FOR (i, 1, 70) {
        ans = min(ans, cal(x));
        x *= 2;
    }
    if (ans > lim) {
        cout << "INVALID\n";
        return;
    }
    cout << ans << '\n';
}

int32_t main() {
    Waimai;
    solve();
}