#include<bits/stdc++.h>
using namespace std;
int bk(int x,int s){
	x-=s;
	int sr;
	char a;
	while(a!=' ')cin>>a;
	if(a=='B'){
		scanf("K %d ",&sr);
		x=bk(x,sr);
	}
	if(a=='F'){
		scanf("D %d ",&sr);
		x=fd(x,sr);
	}
	if(a=='R'){
		scanf("EPEAT %d[",&sr);
		x=repeat(x,sr);
	}
	return x;
}
int fd(int x,int s){
	x+=s;
	int sr;
	char a;
	while(a!=' ')cin>>a;
	if(a=='B'){
		scanf("K %d ",&sr);
		x=bk(x,sr);
	}
	if(a=='F'){
		scanf("D %d ",&sr);
		x=fd(x,sr);
	}
	if(a=='R'){
		scanf("EPEAT %d[",&sr);
		x=repeat(x,sr);
	}
	return x;
}
int repeat(int x,int s){
	for(int i=0;i<s;i++){
		int sr;
		char a;
		while(a!=' ')cin>>a;
		if(a=='B'){
			scanf("K %d ",&sr);
			x=bk(x,sr);
		}
		if(a=='F'){
			scanf("D %d ",&sr);
			x=fd(x,sr);
		}
		if(a=='R'){
			scanf("EPEAT %d[",&sr);
			x=repeat(x,sr);
		}
	}
	scanf("]");
	return x;
}
int main(){
	char a;
	int sr;
	while(a!=' ')cin>>a;
	if(a[0]=='B'){
		scanf("K %d ",&sr);
		printf("%d",abs(bk(sr)));
	}
	if(a[0]=='F'){
		scanf("D %d ",&sr);
		printf("%d",abs(fd(sr)));
	}
	if(a[0]=='R'){
		scanf("EPEAT %d[",&sr);
		repeat(sr);
	}
	return 0;
}