View Compilation Error

0_0_31559875_1343.cpp: In function 'int main()':
0_0_31559875_1343.cpp:6:23: error: unable to find numeric literal operator 'operator""n'
  printf("%d\n",(n*n*n+5n)/6+1);
                       ^
0_0_31559875_1343.cpp:6:23: note: use -std=gnu++11 or -fext-numeric-literals to enable more built-in suffixes