Language: C++

#include<bits/stdc++.h>//atcoder.126.B
using namespce std;
int main(){
	bool a=0,b=0;
	string s;
	getline(cin,s);
	if((s[0]!=0||s[1]!=0)&&((s[3]-96)*10+s[4]>0)&&((s[3]-96)*10+s[4]<=12))a=1;
	if((s[3]!=0||s[4]!=0)&&((s[1]-96)*10+s[2]>0)&&((s[1]-96)*10+s[2]<=12))b=1;
	if(a==0&&b==0)cout<<'NA';
	if(a==1&&b==0)cout<<'YYMM';
	if(a==0&&b==1)cout<<'MMYY';
	if(a==1&&b==1)cout<<'AMBIGUOUS';
	return 0;
}

Compiler output:
a.cc:9:29: warning: multi-character character constant [-Wmultichar]
    9 |         if(a==0&&b==0)cout<<'NA';
      |                             ^~~~
a.cc:10:29: warning: multi-character character constant [-Wmultichar]
   10 |         if(a==1&&b==0)cout<<'YYMM';
      |                             ^~~~~~
a.cc:11:29: warning: multi-character character constant [-Wmultichar]
   11 |         if(a==0&&b==1)cout<<'MMYY';
      |                             ^~~~~~
a.cc:12:29: warning: multi-character literal with 9 characters exceeds 'int' size of 4 bytes
   12 |         if(a==1&&b==1)cout<<'AMBIGUOUS';
      |                             ^~~~~~~~~~~
a.cc:2:7: error: expected nested-name-specifier before 'namespce'
    2 | using namespce std;
      |       ^~~~~~~~
a.cc: In function 'int main()':
a.cc:5:9: error: 'string' was not declared in this scope
    5 |         string s;
      |         ^~~~~~
a.cc:5:9: note: suggested alternatives:
In file included from /usr/include/c++/14/string:41,
                 from /usr/include/c++/14/bitset:52,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:52,
                 from a.cc:1:
/usr/include/c++/14/bits/stringfwd.h:77:33: note:   'std::string'
   77 |   typedef basic_string<char>    string;
      |                                 ^~~~~~
/usr/include/c++/14/string:76:11: note:   'std::pmr::string'
   76 |     using string    = basic_string<char>;
      |           ^~~~~~
a.cc:6:17: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
    6 |         getline(cin,s);
      |                 ^~~
      |                 std::cin
In file included from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:146:
/usr/include/c++/14/iostream:62:18: note: 'std::cin' declared here
   62 |   extern istream cin;           ///< Linked to standard input
      |                  ^~~
a.cc:6:21: error: 's' was not declared in this scope
    6 |         getline(cin,s);
      |                     ^
a.cc:9:23: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
    9 |         if(a==0&&b==0)cout<<'NA';
      |                       ^~~~
      |                       std::cout
/usr/include/c++/14/iostream:63:18: note: 'std::cout' declared here
   63 |   extern ostream cout;          ///< Linked to standard output
      |                  ^~~~
a.cc:10:23: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   10 |         if(a==1&&b==0)cout<<'YYMM';
      |                       ^~~~
      |                       std::cout
/usr/include/c++/14/iostream:63:18: note: 'std::cout' declared here
   63 |   extern ostream cout;          ///< Linked to standard output
      |                  ^~~~
a.cc:11:23: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   11 |         if(a==0&&b==1)cout<<'MMYY';
      |                       ^~~~
      |                       std::cout
/usr/include/c++/14/iostream:63:18: note: 'std::cout' declared here
   63 |   extern ostream cout;          ///< Linked to standard output
      |                  ^~~~
a.cc:12:23: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   12 |         if(a==1&&b==1)cout<<'AMBIGUOUS';
      |                       ^~~~
      |                       std::cout
/usr/include/c++/14/iostream:63:18: note: 'std::cout' declared here
   63 |   extern ostream cout;          ///< Linked to standard output
      |                  ^~~~