View Compilation Error

0_0_38687543_31483.cpp:4:1: error: 'll' does not name a type; did you mean 'LL'?
    4 | ll fastPower(ll base, ll power) {
      | ^~
      | LL
0_0_38687543_31483.cpp: In function 'int main()':
0_0_38687543_31483.cpp:22:25: error: 'fastPower' was not declared in this scope
   22 |                 cout << fastPower(2,a - 1) << endl;
      |                         ^~~~~~~~~