/*
* Author: Nonoze
* Created: Saturday 03/01/2026
*/
#include <bits/stdc++.h>
using namespace std;
#ifndef DEBUG
#define dbg(...)
#endif
// #define cout cerr << "OUT: "
#define endl '\n'
#define endlfl '\n' << flush
#define quit(x) return (void)(cout << x << endl)
template<typename T> void read(T& x) { cin >> x; }
template<typename T1, typename T2> void read(pair<T1, T2>& p) { read(p.first), read(p.second); }
template<typename T> void read(vector<T>& v) { for (auto& x : v) read(x); }
template<typename T1, typename T2> void read(T1& x, T2& y) { read(x), read(y); }
template<typename T1, typename T2, typename T3> void read(T1& x, T2& y, T3& z) { read(x), read(y), read(z); }
template<typename T1, typename T2, typename T3, typename T4> void read(T1& x, T2& y, T3& z, T4& zz) { read(x), read(y), read(z), read(zz); }
template<typename T> void print(vector<T>& v) { for (auto& x : v) cout << x << ' '; cout << endl; }
#define sz(x) (int)(x.size())
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define make_unique(v) sort(all(v)), v.erase(unique(all(v)), (v).end())
#define pb push_back
#define mp(a, b) make_pair(a, b)
#define fi first
#define se second
#define cmin(a, b) a = min(a, b)
#define cmax(a, b) a = max(a, b)
#define YES cout << "YES" << endl
#define NO cout << "NO" << endl
#define QYES quit("YES")
#define QNO quit("NO")
#define int long long
#define double long double
const int inf = numeric_limits<int>::max() / 4;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const int MOD = 1e9+7, LOG=20;
void solve();
signed main() {
ios::sync_with_stdio(0);
cin.tie(0);
int tt=1;
// cin >> tt;
while(tt--) solve();
return 0;
}
int n, m;
void solve() {
read(n, m);
string x, y; read(x, y);
const int CHUNK = 10;
vector<int> a, b;
for (int i=n-1; i>=0; i-=CHUNK) {
a.pb(stoi(x.substr(max(0LL, i-CHUNK+1), min(CHUNK, i+1))));
}
for (int i=m-1; i>=0; i-=CHUNK) {
b.pb(stoi(y.substr(max(0LL, i-CHUNK+1), min(CHUNK, i+1))));
}
n=sz(a), m=sz(b);
vector<__int128_t> res(n+m+2, 0);
for (int i=0; i<n; i++) {
for (int j=0; j<m; j++) {
res[i+j] += a[i]*b[j];
}
}
for (int i=0; i<=n+m; i++) {
res[i+1] += res[i]/(int)(1e10);
res[i] %= (int)(1e10);
}
while (sz(res)>1 && res.back()==0) res.pop_back();
reverse(all(res));
for (int i=0; i<sz(res); i++) {
if (i>0) {
cout << setw(CHUNK) << setfill('0') << (int)res[i];
} else {
cout << (int)res[i];
}
}
}
