View Compilation Error

0_0_13870659_16627.cpp: In function 'int main()':
0_0_13870659_16627.cpp:18:5: error: 'cin' was not declared in this scope
     cin >> t;
     ^
0_0_13870659_16627.cpp:44:9: error: 'cout' was not declared in this scope
         cout << ans << endl;
         ^
0_0_13870659_16627.cpp:44:24: error: 'endl' was not declared in this scope
         cout << ans << endl;
                        ^