View Compilation Error

0_0_17854231_30344.cpp: In function 'int main()':
0_0_17854231_30344.cpp:7:17: error: 'n' was not declared in this scope
 f[i] = 3*(1LL<<(n-1)) - f[i-1];
                 ^
0_0_17854231_30344.cpp:9:7: error: 'cin' was not declared in this scope
 while(cin>>n){
       ^
0_0_17854231_30344.cpp:9:12: error: 'n' was not declared in this scope
 while(cin>>n){
            ^
0_0_17854231_30344.cpp:10:1: error: 'cout' was not declared in this scope
 cout<<f[i]<<endl;
 ^
0_0_17854231_30344.cpp:10:9: error: 'i' was not declared in this scope
 cout<<f[i]<<endl;
         ^
0_0_17854231_30344.cpp:10:13: error: 'endl' was not declared in this scope
 cout<<f[i]<<endl;
             ^