using namespace std;
#include <string>
#include <iostream>
#include <string>
// Hello
 
// Define the digits. //
//--	using namespace std;
char digits[]=  {'0','1','2','3','4','5','6','7','8','9','\0'};
char one[]=  {'1', '\0'};
char zero[]=  {'0', '\0'};
 
// Prototypes for functions that perform integer calculations. // 
char* sum( char a[], char b[] );		// Returns a + b
char* diff( char a[], char b[] );		// Returns a - b
char* product( char a[], char b[] );	// Returns a * b
//--	bool equal( char a[], char b[] );		// True iff a == b
 
// Function to calculate factorial (recursively). //
char* factorial( char n[] ) {
	if (equal( n, zero )) return one;			// 0! is 1
	if (equal( n, zero )) return one;			// 1! is 1
	return product( n, factorial( diff(n,one) ) );	// n! = n*(n-1)!
}
 
// Now, code the functions to perform arithmetic. //
char* sum( char a[], char b[] )		// Returns a + b
{
	int j;
	for (j=0; j<length(a); ++j )
	{
		// ++++ WRITE YOUR OWN CODE HERE +++
	}
}
// . . .
// ++++ ADD YOUR OWN CODE BELOW +++
 
int main()
{
	cout << "Hello\n";
		// ++++ WRITE YOUR OWN CODE HERE +++	
	exit(0);
}