#include <iostream>
#include <regex>
#include <string>

int main() {
  std::string line;
  std::regex r{"(mul\\((\\d+),(\\d+)\\)|do\\(\\)|don't\\(\\))"};
  int result = 0;
  bool enabled = true;
  while (std::getline(std::cin, line)) {
    for (std::sregex_iterator iter{line.begin(), line.end(), r}, iter_end; iter != iter_end; iter++) {
      const auto &match = *iter;
      if (match[1] == "do()") {
        enabled = true;
      } else if (match[1] == "don't()") {
        enabled = false;
      } else if (enabled) {
        const auto op1 = std::stoi(match[2]), op2 = std::stoi(match[3]);
        result += op1 * op2;
      }
    }
  }
  std::cout << result << std::endl;
  return EXIT_SUCCESS;
}