def caesar_work(_direction, _language, _step, _string):

    string_arr = list(_string)
    if _direction == 'E' and _language == 'EN':
        for i in range(len(string_arr)):
            if string_arr[i].isupper():
                if ord(string_arr[i])+ _step > ord('Z'):
                    string_arr[i] = chr(ord(string_arr[i]) + _step - 26)
                else:
                    string_arr[i] = chr(ord(string_arr[i]) + _step)
            elif string_arr[i].islower():
                if ord(string_arr[i])+ _step > ord('z'):
                    string_arr[i] = chr(ord(string_arr[i]) + _step - 26)
                else:
                    string_arr[i] = chr(ord(string_arr[i]) + _step)
    elif _direction == 'E' and _language == 'RU':
        for i in range(len(string_arr)):
            if string_arr[i].isupper():
                if ord(string_arr[i])+ _step > ord('Я'):
                    string_arr[i] = chr(ord(string_arr[i]) + _step - 32)
                else:
                    string_arr[i] = chr(ord(string_arr[i]) + _step)
            elif string_arr[i].islower():
                if ord(string_arr[i])+ _step > ord('я'):
                    string_arr[i] = chr(ord(string_arr[i]) + _step - 32)
                else:
                    string_arr[i] = chr(ord(string_arr[i]) + _step)
    elif _direction == 'D' and _language == 'RU':
        for i in range(len(string_arr)):
            if string_arr[i].isupper():
                if ord(string_arr[i])+ _step < ord('А'):
                    string_arr[i] = chr(ord(string_arr[i]) - _step + 32)
                else:
                    string_arr[i] = chr(ord(string_arr[i]) - _step)
            elif string_arr[i].islower():
                if ord(string_arr[i])+ _step < ord('а'):
                    string_arr[i] = chr(ord(string_arr[i]) - _step + 32)
                else:
                    string_arr[i] = chr(ord(string_arr[i]) - _step)
    elif _direction == 'D' and _language == 'EN':
        for i in range(len(string_arr)):
            if string_arr[i].isupper():
                if ord(string_arr[i])+ _step < ord('A'):
                    string_arr[i] = chr(ord(string_arr[i]) - _step + 26)
                else:
                    string_arr[i] = chr(ord(string_arr[i]) - _step)
            elif string_arr[i].islower():
                if ord(string_arr[i])+ _step < ord('a'):
                    string_arr[i] = chr(ord(string_arr[i]) - _step + 26)
                else:
                    string_arr[i] = chr(ord(string_arr[i]) - _step)
    string_result = ''.join(string_arr)
    print(string_result)



print("Let's encrypt or decrypt your phrase")
print()

direction = input('Encryption or decryption? Enter E or D: ', )
while direction != 'E' and direction != 'D':
    direction = input('Please enter E or D! ')

language = input('What language do you want to use? Enter RU or EN: ')
while language != 'RU' and language != 'EN':
    language = input('Please enter RU or EN! ')

step = input('What shear step do you want to use? Enter an integer number: ')
while step.isdigit() == False:
    step = input('Please enter an integer number: ')
step = int(step)

string = input('Enter a string: ')
caesar_work(direction, language, step, string)