/in/foo.cc: In function 'int main()':
/in/foo.cc:8:8: error: no match for 'operator<<' (operand types are 'std::istream {aka std::basic_istream<char>}' and 'long long int')
     cin<<a<<b;
        ^
/in/foo.cc:8:8: note: candidate: operator<<(int, long long int) <built-in>
/in/foo.cc:8:8: note:   no known conversion for argument 1 from 'std::istream {aka std::basic_istream<char>}' to 'int'