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

int main() {
	ios_base::sync_with_stdio(false), cin.tie(nullptr);
	string st;
	cin >> st;
	__int128 ans = 1e36;
	for (__int128 j = 4; j <= (1LL << 62); j <<= 1) {
		__int128 now = j;
		for (int i = ((int)st.size()) - 1; i >= 0; --i) {
			if (st[i] == 'O' && ((now & 1) || (now - 1) % 3 != 0)) break;
			if (st[i] == 'E' && (now & (now - 1)) == 0) break;
			if (st[i] == 'O') now = (now - 1) / 3;
			if (st[i] == 'E') now = now * 2;

			if (i == 0) ans = min(ans, now);
		}
	}
	if (ans == (__int128)1e36) cout << "INVALID\n";
	else cout << (long long)ans << endl;
	return 0;
}