up08-3 (grammar 1)

#include <iostream>
#include <map>
#include <string>
#include <algorithm>
#include <cctype>

std::string to_lower(const std::string &s)
{
    std::string data(s);
    std::transform(data.begin(), data.end(), data.begin(), [](unsigned char c) { return std::tolower(c); });
    return data;
}


bool is_grammar(const std::multimap<std::string, std::string> &dict)
{
    if (dict.empty() || dict.count(std::string("S")) == 0) {
        return false;
    }
    for (auto &c:dict) {
        if (c.first == to_lower(c.first)) {
            return false;
        }
    }
    return true;
}

bool is_context_free(const std::multimap<std::string, std::string> &dict)
{
    for (auto &c:dict) {
        if (c.first.size() != 1 || c.first[0] != std::toupper(c.first[0])) {
            return false;
        }
    }
    return true;
}

bool is_inconclusive_context_free(const std::multimap<std::string, std::string> &dict)
{
    bool flag1 = false;
    bool flag2 = false;
    if (!is_context_free(dict)) {
        return false;
    }
    for (auto &c:dict) {
        if (c.second.find("S") != std::string::npos) {
            flag1 = true;
        }
        if (c.second == "_") {
            if (c.first != "S") {
                return false;
            } else {
                flag2 = true;
            }
        }
    }
    return !(flag1 && flag2);
}

int main()
{
    std::multimap<std::string, std::string> dict;
    std::string key, value;
    while (std::cin >> key >> value) {
        dict.insert({key, value});
    }
    if (!is_grammar(dict)) {
        std::cout << "-1" << std::endl;
    } else {
        if (is_inconclusive_context_free(dict)) {
            std::cout << "23" << std::endl;
        } else if (is_context_free(dict)) {
            std::cout << "2" << std::endl;
        } else {
            std::cout << "10" << std::endl;
        }
    }
}