Russian and English contain the same letters. Can I identify, in the line only English letters? Or vice versa: did the string contain Russian letters? But in this line there will be numbers. For example:
English only: "123English"
Only Russians: "123Русский"
Both Russian and English: "456EnglishРусский"
English only: "123English"
Only Russians: "123Русский"
Both Russian and English: "456EnglishРусский"