#include <iostream>
#include <cstring>

int numDigits(int number)
{
    int digits = 0;
    while (number) {
        number /= 10;
        digits++;
    }
    return digits;
}


int isValidExpr(char* expr) {
    if (strcmp(expr, "zero") == 0)
        return 0;
    else if (strcmp(expr, "one") == 0)
        return 1;
    else if (strcmp(expr, "two") == 0)
        return 2;
    else if (strcmp(expr, "three") == 0)
        return 3;
    else if (strcmp(expr, "four") == 0)
        return 4;
    else if (strcmp(expr, "five") == 0)
        return 5;
    else if (strcmp(expr, "six") == 0)
        return 6;
    else if (strcmp(expr, "seven") == 0)
        return 7;
    else if (strcmp(expr, "eight") == 0)
        return 8;
    else if (strcmp(expr, "nine") == 0)
        return 9;
    else if (strcmp(expr, "plus") == 0)
        return 10;
    else if (strcmp(expr, "minus") == 0)
        return 11;
    else
        return -1;
}

void calculateExpression(char* expr) {
    int result = 0;
    int i = 0;
    int j = 0;
    char substr[1024];
    bool isAtPlus = true;
    int lastExpr = 0;

    while (expr[i] != '\0')
    {
        substr[j] = expr[i];
        substr[j + 1] = '\0';
        if (isValidExpr(substr) != -1)
        {
            int expr = isValidExpr(substr);
            if (expr == 10)
            {
                if (isAtPlus)
                    result += lastExpr;
                else
                    result -= lastExpr;

                isAtPlus = true;
                lastExpr = 0;
            }
            else if (expr == 11)
            {
                if (isAtPlus)
                    result += lastExpr;
                else
                    result -= lastExpr;

                isAtPlus = false;
                lastExpr = 0;
            }
            else
            {
                lastExpr = lastExpr * 10 + expr;
            }
            j = 0;
            ++i;
            continue;
        }

        ++i;
        ++j;
    }

    if (isAtPlus)
        result += lastExpr;
    else
        result -= lastExpr;

    int number = result;
    char numberArray[124];

    bool isNegative = number < 0;
    if (isNegative)
        number *= -1;

    for (i = 0; number != 0; ++i, number /= 10)
    {
        numberArray[i] = number % 10 + '0';
    }
    numberArray[i--] = '\0';
    char resultString[124];

    if (isNegative)
    {
        resultString[0] = '-';
        j++;
    }
    while (i >= 0)
    {
        resultString[j] = numberArray[i];
        j++;
        i--;
    }
    resultString[j] = '\0';
    strcpy_s(expr, strlen(expr), resultString);
}

int main()
{
    int size;
    std::cout << "Enter string's size: ";
    std::cin >> size;
    std::cout << "Enter the string: ";
    char* arr = new char[size + 1];
    std::cin >> arr;
    calculateExpression(arr);
    std::cout << arr;

    delete [] arr;
}