#include<bits/stdc++.h>
using namespace std;
typedef long long LL;
typedef __int128 LLL;
const int MAXN = 1000006;

char s[100];
int n;

inline bool Check(LLL x) {
    while (!(x & 1)) {
        x >>= 1;
    }
    return (x == 1);
}

void solve() {
    scanf("%s", s + 1);
    n = strlen(s + 1);
    for (int i = 2; i <= 75; ++i) {
        LLL cur = ((LLL)1 << i);
        bool flag = 1;
        for (int j = n; j >= 1; --j) {
            if (s[j] == 'E') {
                cur = cur * 2;
            } else {
                if ((cur - 1) % 3) {
                    flag = 0;
                    break;
                }
                cur = (cur - 1) / 3;
                if (!(cur & 1)) {
                    flag = 0;
                    break;
                }
            }
            if (Check(cur)) {
                flag = 0;
                break;
            }
        }
        if (flag && cur <= (1LL << 47)) {
            printf("%lld\n", (LL)cur);
            return;
        }
    }
    puts("INVALID");
}

int main() {
    solve();
    return 0;
}