ModAdd

#include<iostream>
#include<string>


int main(){
  std::cin.tie(NULL);
  std::ios_base::sync_with_stdio(0);
  std::string a,b;
  std::cin>>a>>b;
  long long at_a,at_b;
  long long lena=a.length()-1;
  long long lenb=b.length()-1;
  int last=1;
  int ans;
  if(lena<lenb){
  for(long long i=0;i<lenb-lena;i++){
    std::cout<<b[i];
  }
  for(long long i=0;i<=lena;i++){
    long long ii=lena-i;
    at_a=a[lena-ii]-'0';
    at_b=b[lenb-ii]-'0';
    ans=(at_a+at_b)%10;
    if(ans==0){
    if(last==0){
    std::cout<<std::endl;exit(0);}}last=ans;
    std::cout<<ans;
    
    
  }
  std::cout<<std::endl;
  }
  else{
  for(long long i=0;i<lena-lenb;i++){
    std::cout<<a[i];
  }
  for(long long i=0;i<=lenb;i++){
    long long ii=lenb-i;
    at_a=a[lena-ii]-'0';
    at_b=b[lenb-ii]-'0';
    ans=(at_a+at_b)%10;
    if(ans==0){
    if(last==0){
    std::cout<<std::endl;exit(0);}}last=ans;
    std::cout<<ans;
    
  }
  std::cout<<std::endl;
  }
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: WRONG ANSWER

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: WRONG ANSWER