C++ unordered_map no matching member function for call to 'find'

I'm trying to initialize an unordered_map in c++ and then run the find command, it keeps failing with this error and I'm not sure what to do next. This is in leetcode if that helps.

string num = "10003";
unordered_map<string,string> mymap = {
            {"0","0"},
            {"1","1"},
            {"6","9"},
            {"8","8"},
            {"9","6"},
        };
        unordered_map<string,string>::const_iterator got;
        for (auto s: num){
            mymap.find(s);
        }

Line 15: Char 19: error: no matching member function for call to 'find'
            mymap.find(s);
            ~~~~~~^~~~
/usr/bin/../lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/unordered_map.h:920:7: note: candidate function not viable: no known conversion from 'char' to 'const std::unordered_map<std::__cxx11::basic_string<char>, std::__cxx11::basic_string<char>, std::hash<std::string>, std::equal_to<std::__cxx11::basic_string<char>>, std::allocator<std::pair<const std::__cxx11::basic_string<char>, std::__cxx11::basic_string<char>>>>::key_type' (aka 'const std::__cxx11::basic_string<char>') for 1st argument
      find(const key_type& __x)
      ^
/usr/bin/../lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/unordered_map.h:924:7: note: candidate function not viable: no known conversion from 'char' to 'const std::unordered_map<std::__cxx11::basic_string<char>, std::__cxx11::basic_string<char>, std::hash<std::string>, std::equal_to<std::__cxx11::basic_string<char>>, std::allocator<std::pair<const std::__cxx11::basic_string<char>, std::__cxx11::basic_string<char>>>>::key_type' (aka 'const std::__cxx11::basic_string<char>') for 1st argument
      find(const key_type& __x) const
      ^
1 error generated.