int parse_int(string n) {
    int parse_digit(string n) {
        if (ascii(n) >= 48 && ascii(n) <= 57)
            return ascii(n) - 48;
        else
            return -1;
    } 
 
    bool is_int(string idk) {
        bool yes = true;
        string n;
 
        for (int i = 0; i < length(idk); ++i) {
            n = substr(idk, i, 1);
            if (parse_digit(n) == -1) {
                yes = false;
                break;
            }
        }
 
        return yes;
    }
 
    int multiplier = 1;
    int start_index = 0;
 
    if (substr(n,0,1) == "-") {
        multiplier = -1;
        start_index = 1;
    }
 
    if (is_int(n)) {
        int result = 0;
        for (int i = start_index; i < length(n); ++i) {
            result += parse_digit(substr(n,i,1))*10^(length(n) - i - 1);
          }
        return multiplier * result;
    }
    else {
        return 0;
    }
}