#include <stdio.h>
#include <stdlib.h>
#define N 50000
#define M 50000
#define L 17 /* L = ceil(log2(N + M)) */
#define N_ (1 << L)
#define MD 998244353
long long power(long long a, int k) {
long long p = 1;
while (k) {
if (k & 1)
p = p * a % MD;
a = a * a % MD;
k >>= 1;
}
return p;
}
int *wwu[L + 1], *wwv[L + 1], vv_[L + 1];
void init() {
int l, u, v;
u = power(3, MD - 1 >> L), v = power(u, MD - 2);
for (l = L; l > 0; l--) {
int n = 1 << l, m = n >> 1, i;
vv_[l] = power(n, MD - 2);
wwu[l] = (int *) malloc(m * sizeof *wwu[l]);
wwv[l] = (int *) malloc(m * sizeof *wwv[l]);
wwu[l][0] = wwv[l][0] = 1;
for (i = 1; i < m; i++) {
wwu[l][i] = (long long) wwu[l][i - 1] * u % MD;
wwv[l][i] = (long long) wwv[l][i - 1] * v % MD;
}
u = (long long) u * u % MD, v = (long long) v * v % MD;
}
vv_[0] = 1;
}
void ntt_(int *aa, int l, int inverse) {
if (l) {
int n = 1 << l, m = n >> 1, *ww = inverse ? wwv[l] : wwu[l], i, j;
ntt_(aa, l - 1, inverse), ntt_(aa + m, l - 1, inverse);
for (i = 0; (j = i + m) < n; i++) {
int a = aa[i], b = (long long) aa[j] * ww[i] % MD;
if ((aa[i] = a + b) >= MD)
aa[i] -= MD;
if ((aa[j] = a - b) < 0)
aa[j] += MD;
}
}
}
void ntt(int *aa, int l, int inverse) {
int n = 1 << l, i, j;
for (i = 0, j = 1; j < n; j++) {
int m = n >> 1, tmp;
while ((i ^= m) < m)
m >>= 1;
if (i < j)
tmp = aa[i], aa[i] = aa[j], aa[j] = tmp;
}
ntt_(aa, l, inverse);
}
int main() {
static char aa[N + 1], bb[M + 1];
static int aa_[N_], bb_[N_], cc[N + M];
int n, m, n_, l_, i, j;
init();
scanf("%d%d%s%s", &n, &m, aa, bb);
for (i = 0; i < n; i++)
aa_[i] = aa[n - 1 - i] - '0';
for (j = 0; j < m; j++)
bb_[j] = bb[m - 1 - j] - '0';
l_ = 0;
while (1 << l_ < n + m)
l_++;
n_ = 1 << l_;
ntt(aa_, l_, 0), ntt(bb_, l_, 0);
for (i = 0; i < n_; i++)
aa_[i] = (long long) aa_[i] * bb_[i] % MD;
ntt(aa_, l_, 1);
for (i = 0; i < n_; i++)
aa_[i] = (long long) aa_[i] * vv_[l_] % MD;
for (i = 0; i + 1 < n + m; i++) {
cc[i] += aa_[i];
cc[i + 1] += cc[i] / 10, cc[i] %= 10;
}
i = n + m - 1;
while (i > 0 && cc[i] == 0)
i--;
while (i >= 0)
printf("%d", cc[i--]);
printf("\n");
return 0;
}
