#include <iostream>
#include <string>
#include <list>
#include <algorithm>

bool is_not_a_letter(const char c)
{
    return !isalpha(c);
}

int main()
{
    std::string s(":;[{abcd V 8239234");

    s.erase(std::remove_if(s.begin(),
                           s.end(),
                           is_not_a_letter),
            s.end());

    std::cout << s << "\n";
    return 0;
}