#include <cstdlib> #include <iostream> #include <cstring> #include <cstdio> #include <algorithm> #include <string> using namespace std; int main() { string a, b; while (cin >> a >> b) { int num1=atoi(a.c_str())+atoi(b.c_str()); reverse(a.begin(),a.end()); reverse(b.begin(),b.end()); int num2=atoi(a.c_str())+atoi(b.c_str()); string str1=to_string(num1); string str2=to_string(num2); reverse(str2.begin(),str2.end()); if(str1==str2) { cout<<num1<<endl; } else { cout<<"NO"<<endl; } } return 0; }