#include<bits/stdc++.h>
#define endl "\n"
#define int long long
#define PII std::pair<int,int>
#define IOS ios::sync_with_stdio(false);cin.tie(0);
#define inf 0x3f3f3f3f

using namespace std;
set<int>st;
void init()
{
	int x=1;
	for(int i=1;i<50;i++)
	{
		st.insert(x);
		x*=2;
//		cout<<x<<endl;
	}
}
void solve()
{
	string s;
	cin>>s;
	int n=s.length();
	s="!"+s;
	init();
	if(s[n]=='E')
	{
		cout<<"INVALID"<<endl;
		exit(0);
	}
	for(int a:st)
	{
//		int b=a;
		if(a==1||a==2) continue;
			for(int i=n;i>=1;i--)
			{
				
				if(s[i]=='E')
					a*=2;
				else 
				{
					if(i!=s.length()&&s[i+1]=='O')
					{
						cout<<"INVALID"<<endl;
						exit(0);
					}
					if(a%3!=1) break;
					a=(a-1)/3;
				}
				if(st.find(a)!=st.end())
					{
//					cout<<"YES"<<endl;
					break;
				}
				if(i==1)
				{
					cout<<a<<endl;
					exit(0);
				}
			}
		
	}
}

signed main() {
    IOS;cout.tie(0);
	int t=1;
//    cin>>t;
	while(t--)
	{
		solve();
	}
	
}