#include <stdio.h>
#include <stdlib.h>

int isZero(int* a)
{
	if (a[0] == 0)
		return 1;
	int i = 1;
	for (; i<=a[0]; i++)
		if (a[i] != 0)
			return 0;
	return 1;
}

long long int arr2long (int* a)
{
	if (a[0] == 0)
		return 0;
	long long int p2 = 1;
	p2 <<= (a[0]-1); // a[0] <= 30
	long long int res = 0;
	int i;
	for (i=1; i<=a[0]; i+=1, p2>>=1)
		res += (long long int)a[i]*p2;
	return res;
}

int* long2arr (long long int a)
{
	int* res = (int*) malloc(260);
	int i;
	for (i = 64; a > 0; i--)
	{
		res[i] = a & 1;
		a = a >> 1;
	}
	res[i] = 64 - i;
	res = res + i;
	return res;
}

int* prepend(int* bin, int n)
{
	int i = 1;
	int* res = (int*) malloc((n+bin[0]+1) << 2);
	res[0] = bin[0]+n;
	for (; i<=n; i++)
		res[i] = 0;
	for (i=1; i<=bin[0]; i++)
		res[n+i] = bin[i];
	return res;
}

void bin2hex(int* bin) {
	int i;
	int r = bin[0] & 3;
	if (r)
		bin = prepend(bin, 4-r);
	for (i = 1; i < bin[0]; i += 4) {
		int j;
		int n = 0;
		for (j = 0; j < 4; j++)
			n = n * 2 + bin[i + j];
		if( n < 10 )
			putchar(n+48);
		else
			putchar(n+55);
	}
}

int* add(int* a, int* b) {
	if (a[0] < b[0])
		return add(b, a);
	else if (a[0] > b[0])
		return add(a, prepend(b,a[0]-b[0]));

	int n = a[0];
	int *ans = (int *) malloc((n + 2) << 2);
	ans[0] = n + 1;
	int i, carry = 0;
	for (i = n + 1; i > 1; i--) {
		ans[i] = a[i - 1] + b[i - 1] + carry;
		carry = ans[i] >> 1;
		ans[i] = ans[i] & 1;
	}
	ans[1] = carry;

	return ans;		// length n+1
}

void print(int* a) {
	int i, n = a[0];
	for (i = 1; i <= n; i++)
		printf("%d", a[i]);
	printf("\n");
}

int* sub(int* a, int* b) {
	if (a[0] > b[0])
		return sub(a, prepend(b,a[0]-b[0]));

	int n = a[0];
	int *ans = (int *) malloc((n + 1) << 2);
	ans[0] = n;
	int i, borrow = 0;
	for (i = n; i > 0; i--) {
		ans[i] = a[i] - b[i] - borrow;
		borrow = 0;
		if( ans[i] < 0 )	{
			borrow = 1;
			ans[i] &= 1;
		}
	}

	return ans;		// length n+1
}



int* mul2(int* a) {
	int *res = (int *) malloc((a[0] + 2) << 2);

	int i;
	res[0] = a[0] + 1;

	for (i = 1; i <= a[0]; i++)
		res[i] = a[i];
	res[i] = 0;

	return res;		// length n+1
}

void chunkify(int *a, int *A[2])	{
	int n1, n2;
	n1 = a[0]/2;
	n2 = a[0] - n1;

	A[0] = (int*) malloc((n1+1) << 2);
	A[1] = (int*) malloc((n2+1) << 2);
	A[0][0] = n1;
	A[1][0] = n2;

	int i, j;
	for(i = 1; i <= n1; ++i)
		A[0][i] = a[i];
	for(j = 1; j <= n2; ++i, ++j)
		A[1][j] = a[i];
}

int* shiftAndAdd(int* a, int* b, int* c, int x)
{	// assumption: a is the least significant chunk
	int i;
	for (i=0; i<x; i++)
		b = mul2(b);
	for (i=0; i<2*x; i++)
		c = mul2(c);
	int* res = add(add(a,b),c);
	return res;
}

int* karatsuba(int* a, int* b) {
	if(isZero(a) || isZero(b))	{
		int* r = malloc(4);
		*r = 0;
		return r;
	}
	if(a[0] < b[0])
		return karatsuba(prepend(a,b[0]-a[0]), b);
	if(a[0] > b[0])
		return karatsuba(a, prepend(b, a[0]-b[0]));
	if(a[0] <= 30)	{
		long long int A = arr2long(a), B = arr2long(b), C;
		C = A*B;
		return long2arr(C);
	}

	int *A[2], *B[2];
	chunkify(a,A);
	chunkify(b,B);
	if(isZero(A[0]) && isZero(B[0]))	{
		return karatsuba(A[1],B[1]);
	}
	int x = A[1][0];
	int* z2 = karatsuba(A[0], B[0]);
	int* z0 = karatsuba(A[1], B[1]);
	int* z1 = sub(sub(karatsuba(add(A[1],A[0]),add(B[1],B[0])),z0),z2);
	int* r = shiftAndAdd(z0, z1, z2, x);
	return r;
}


void hex2bin(int* a, char* s)	{
	int i;
	for(i = 0; s[i] != '\0'; ++i)	{
		int j = i << 2;
		switch(s[i])	{
			case 48:	a[j+1] = 0;
						a[j+2] = 0;
						a[j+3] = 0;
						a[j+4] = 0;
						break;
			case 49:	a[j+1] = 0;
						a[j+2] = 0;
						a[j+3] = 0;
						a[j+4] = 1;
						break;
			case 50:	a[j+1] = 0;
						a[j+2] = 0;
						a[j+3] = 1;
						a[j+4] = 0;
						break;
			case 51:	a[j+1] = 0;
						a[j+2] = 0;
						a[j+3] = 1;
						a[j+4] = 1;
						break;
			case 52:	a[j+1] = 0;
						a[j+2] = 1;
						a[j+3] = 0;
						a[j+4] = 0;
						break;
			case 53:	a[j+1] = 0;
						a[j+2] = 1;
						a[j+3] = 0;
						a[j+4] = 1;
						break;
			case 54:	a[j+1] = 0;
						a[j+2] = 1;
						a[j+3] = 1;
						a[j+4] = 0;
						break;
			case 55:	a[j+1] = 0;
						a[j+2] = 1;
						a[j+3] = 1;
						a[j+4] = 1;
						break;
			case 56:	a[j+1] = 1;
						a[j+2] = 0;
						a[j+3] = 0;
						a[j+4] = 0;
						break;
			case 57:	a[j+1] = 1;
						a[j+2] = 0;
						a[j+3] = 0;
						a[j+4] = 1;
						break;
			case 97:
			case 65:	a[j+1] = 1;
						a[j+2] = 0;
						a[j+3] = 1;
						a[j+4] = 0;
						break;
			case 98:
			case 66:	a[j+1] = 1;
						a[j+2] = 0;
						a[j+3] = 1;
						a[j+4] = 1;
						break;
			case 99:
			case 67:	a[j+1] = 1;
						a[j+2] = 1;
						a[j+3] = 0;
						a[j+4] = 0;
						break;
			case 100:
			case 68:	a[j+1] = 1;
						a[j+2] = 1;
						a[j+3] = 0;
						a[j+4] = 1;
						break;
			case 101:
			case 69:	a[j+1] = 1;
						a[j+2] = 1;
						a[j+3] = 1;
						a[j+4] = 0;
						break;
			case 102:
			case 70:	a[j+1] = 1;
						a[j+2] = 1;
						a[j+3] = 1;
						a[j+4] = 1;
						break;

		}
	}
	a[0] = i << 2;
}

void main(void) {
	int a[1024], b[1024];

	char s1[256], s2[256];
	scanf("%s\n%s", s1, s2);
	hex2bin(a,s1);
	hex2bin(b,s2);

	int *c;
	c = karatsuba(a,b);

	bin2hex(c);
	printf("\n");
}