#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e6 + 10;
string s, t;
int n, a[maxn], b[maxn], f[maxn];
inline void init(string &s) {
  reverse(s.begin(), s.end());
  for(int i = n - s.length() + 1; i; --i) s += '0';
  reverse(s.begin(), s.end());
}
inline string init2(string s) {
  reverse(s.begin(), s.end());
  while(s.back() == '0') s.pop_back();
  reverse(s.begin(), s.end());
  if(s.empty()) s = "0";
  return s;
}
inline string solve(const string &s, const string &t) {
  memset(a, 0, sizeof a), memset(b, 0, sizeof b);

  int l = 0, r = n;
  string ans;
  while(l <= r) {
    int md = l + r >> 1;
    string res;
    for(int i = n; i >= 0; --i) a[n - i] = s[i] - '0';
    for(int i = n; i >= 0; --i) b[n - i] = t[i] - '0';
    for(int i = 0; i < md; ++i) {
      if(a[i] > 9) a[i] = 0, ++a[i + 1];
      if(b[i] < 0) b[i] = 9, --b[i + 1];
      if(a[i]) {
        int d = 10 - a[i];
        if(b[i] >= d) b[i] -= d;
        else b[i] = b[i] + 10 - d, --b[i + 1];
        a[i] = 0, ++a[i + 1], res += d + '0';
      }else res += '0';
    }
    for(int i = md; i <= n; ++i) {
      if(a[i] > 9) a[i] = 0, ++a[i + 1];
      if(b[i] < 0) b[i] = 9, --b[i + 1];
    }
//    cout << "---\n";
//    for(int i = 0; i <= n; ++i) cout << a[i]; cout << '\n';
//    for(int i = 0; i <= n; ++i) cout << b[i]; cout << '\n';
    reverse(res.begin(), res.end());
    bool flag = true;
    for(int i = 0; i <= n; ++i) if(a[i] + b[i] > 9) flag = false;
    if(flag && b[n + 1] == 0) ans = res, r = md - 1;
    else l = md + 1, b[n + 1] = 0;
//    cout << md << ' ' << res << ' ' << flag << '\n';
  }
//  cout << "ans = " << ans << ' ' << ans.length() << ' ' << n << '\n';
  init(ans);
  return ans;
}
inline void solve() {
  cin >> s >> t, n = max(s.length(), t.length());
  init(s), init(t);
  string ans1 = solve(s, t), ans2 = solve(t, s);
  cout << init2(min({s, t, ans1, ans2})) << '\n';
}
int main() {
  ios::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);
  solve();
  return 0;
}