View Compilation Error

0_0_28016213_28677.cpp: In function 'int main()':
0_0_28016213_28677.cpp:6:5: error: 'INT' was not declared in this scope
     INT x = (INT) k * (n - k + 1);
     ^
0_0_28016213_28677.cpp:7:21: error: 'x' was not declared in this scope
     printf("%lld\n",x);
                     ^