#include <bits/stdc++.h>
using namespace std;
int x,q,i,work();
string s;

void qq(){
	while(s[i]<'0'||s[i]>'9'){i++;}
	q=0;
	while(s[i]>='0' && s[i] <= '9'){
		q = q*10 + (s[i]-'0');
		i++;
	}
}

void FD(){
	qq();
	x += q;
}
void BK(){
	qq();
	x -= q;
}
void REPEAT(){
	qq();
	int ji = i;
	if (s[i] == '['){
		int jq = q;
		for (int j = 1; j <= jq; j++){
			i = ji+1;
			work();
		}
		
	}
}
work(){
	while(i < s.size()){
		if (s[i] == 'F') FD();
		else if (s[i] == 'B') BK();
		else if (s[i] == 'R') REPEAT();
		else if (s[i] == ']') return 1;
		else i++;
	}
}
int main()
{
	getline(cin,s);
	work();
	cout << x;
}

为什么呢QAQ