View Compilation Error

0_0_31470894_20183.cpp:1:1: error: 'The' does not name a type
 The 3n + 1 problem
 ^
0_0_31470894_20183.cpp: In function 'int p(int)':
0_0_31470894_20183.cpp:56:30: error: unable to find numeric literal operator 'operator""a'
                 if(a%2!=0) a=3a+1;
                              ^
0_0_31470894_20183.cpp:56:30: note: use -std=gnu++11 or -fext-numeric-literals to enable more built-in suffixes