foo.cpp: In function 'int main()':
foo.cpp:5:11: error: 'cin' was not declared in this scope
     while(cin>>m>>n)
           ^
foo.cpp:5:11: note: suggested alternative:
In file included from c:\tdm-gcc-32\lib\gcc\mingw32\4.8.1\include\c++\mingw32\bits\stdc++.h:74:0,
                 from foo.cpp:1:
c:\tdm-gcc-32\lib\gcc\mingw32\4.8.1\include\c++\iostream:60:18: note:   'std::cin'
   extern istream cin;  /// Linked to standard input
                  ^