#include <iostream> #include <cstdio> using namespace std; int Reverse(int x){ int num=0; while(x>0){ num+=num*10+x%10; x/=10; } return num; } int main() { int a,b; while(scanf("%d%d",&a,&b)!=EOF){ if(Reverse(a)+Reverse(b)==Reverse(a+b)){ printf("%d",a+b); }else { printf("NO"); } } return 0; } // 64 位输出请用 printf("%lld")