#include<sstream>
#include<string>
using namespace std;
class Solution{
public:
string solve(string s,string t){
int lens=s.size();
int lent=t.size();
if(lens==0){
return t;
}
if(lent==0){
return s;
}
while(lent<lens){
t="0"+t;
lent++;
}
while(lens<lent){
s="0"+s;
lens++;
}
string res;
int carry=0;
int len=lens;
for(int i=len-1;i>=0;i--){
int temp=(s[i]+t[i]-'0'-'0'+carry);
res=char(temp%10+'0')+res;
carry=temp/10;
}
if(carry==1){
res=char(carry+'0')+res;
}
return res;
}
};