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

#define ll long long

string sT = "";
ll i = 0;

ll scf()
{
	ll llK = 0;
	char cA = '\0';
	ll llSum = 0;
	
	for (; i < sT.size(); i++)
	{
		llK = 0;
		
		cA = sT[i];
		
	    if (']' == cA)
		{
			return llSum;
		}
		
		if ('R' == cA)
		{
			i += 7;
			
			while ((sT[i] >= '0') && (sT[i] <= '9'))
			{
				llK = llK * 10 + (ll)(sT[i] - '0');
				
				i++;
			}
			
			llSum += llK * scf();
		}
		else if ('B' == cA)
		{
			i += 3;
			
			while ((sT[i] >= '0') && (sT[i] <= '9'))
			{
				llK = llK * 10 + (ll)(sT[i] - '0');
				
				i++;
			}
			
			llSum -= llK;
		}
		else if ('F' == cA)
		{
			i += 3;
			
			while ((sT[i] >= '0') && (sT[i] <= '9'))
			{
				llK = llK * 10 + (ll)(sT[i] - '0');
				
				i++;
			}
			
			llSum += llK;
		}
	}
		
	return llSum;
}

int main()
{
    getline(cin, sT);
    
	cout << (ll)abs(scf()) << endl;
	
	return 0; 
}