foo.cpp:1:1: error: 'include' does not name a type
 include <iostream> include <stdio.h>
 ^
foo.cpp: In function 'int main()':
foo.cpp:14:18: error: 'scanf' was not declared in this scope
 scanf( "%d" , &n );
                  ^
foo.cpp:21:1: error: 'cout' was not declared in this scope
 cout << ans << endl;
 ^
foo.cpp:21:16: error: 'endl' was not declared in this scope
 cout << ans << endl;
                ^