tyjie

#include<bits/stdc++.h>
using namespace std;
string s;
int func (int l, int r) {
    if (l > r) return 0;
    string t = "";
    while (l <= r && s[l] >= 'A' && s[l] <= 'Z')
        t += s[l++];
    int m = 0;
    while (l <= r && s[l] >= '0' && s[l] <= '9')
        m = m * 10 + s[l++] - '0';
    if (t == "FD") return m + func(l, r);
    else if (t == "BK") return -m + func(l, r);
    else {
        int ans = 0;
        for (int i = l; i <= r; i++) {
            if (s[i] == '[') ans++;
            else if (s[i] == ']') ans--;
            if (ans == 0)
                return m * func(l + 1, i - 1) + func(i + 1, r);
        }
    }
}
int main() {
    string str;
    while (cin >> str) s += str;
    cout << abs(func(0, s.size() - 1));
    return 0;
}