A Plus B

#include <bits/stdc++.h>
using namespace std;
string a,b;
string doi (int x) {
  stringstream ss;
  ss << x;
  return ss.str();
}
string cong(string a,string b) {
    while(a.size()<b.size()) a.insert(0,"0");
    while(a.size()>b.size()) b.insert(0,"0");
    string re = ""; int du = 0;
    for(int i=b.size()-1;i>=0;i--) {
      int t = (int(b[i]) - 48) + (int (a[i]) - 48) + du; du = 0;
      if (t >= 10) t -= 10,du = 1;
      re.insert(0,doi(t));
    }
    if (du != 0) re.insert(0,doi(du));
    return re;
}
int main() 
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL); cout.tie(NULL);
    cin >> a; cin >> b;
    cout << cong(a ,b);
    return 0;
}