#include <stdio.h>
int main()
{
    int a,b,c,d,e;
    scanf("%d%d",&a,&b);
    c = a%10;
    d = b%10;
    e = a+b;
    if(c==0 || d==0)
      printf("%d",e%10);
    else
      printf("%d%d",e%100/10,e%10);
    return 0;
}