#include <iostream>
#include <cstring>

using namespace std;

const int MAX_STRING_SIZE = 4;

int symbColToNumCol(char* colSym, int length) {
	int element = 0;
	int sum = 0;

	if (length == 1) {
		element = colSym[0];
		element = (element - 'A') + 1;
		sum += element;
	}

	else if (length == 2) {
		for (int i = 0; i < length; i++) {
			element = colSym[i];
			element = (element - 'A') + 1;
			if (i == 0) {
				sum = element * 26;
			}
			else if (i == 1) {
				sum += element;
			}
		}
	}
	else {
		for (int i = 0; i < length; i++) {
			element = colSym[i];
			element = (element - 'A') + 1;
			if (i == 0) {
				sum = (pow(26, 2) * element);
			}
			else if (i == 1) {
				sum += (element * 26);
			}
			else {
				sum += element;
			}
		}
	}
	return sum;
}

bool isInputValid(char* str)
{
	int strLength = strlen(str);

	if (strLength >= MAX_STRING_SIZE)
	{
		return false;
	}

	for (int i = 0; i < strLength; i++)
	{
		if (str[i] < 'A' || str[i] > 'Z')
		{
			return false;
		}
	}

	return true;
}

int main()
{
	char colSym[MAX_STRING_SIZE];
	char input[100];

	int length = 0;

	cout << "Please, enter column letter with length 1-3 symbols: ";
	std::cin >> input;

	int nextChar = std::cin.peek();

	while (isInputValid(input) == false || (!isalpha(nextChar) && nextChar != '\n'))
	{

		std::cin.clear();
		std::cin.ignore(INT_MAX, '\n');
		std::cout << "Invalid input!" << std::endl;
		std::cin >> input;

		nextChar = std::cin.peek();
	}

	for (int i = 0; i < strlen(input) + 1; i++)
	{
		colSym[i] = input[i];
	}

	length = strlen(colSym);

	cout << symbColToNumCol(colSym, length);
}