#include<stdio.h>
int main()
{
    int first _reactant,second_reactant;
    if(scanf("%d",&first _reactant) !=1 ||
     scanf("%d",&second_reactant) !=1)
     {
         printf("Invalid input");
         return 0;
     }
     if(first _reactant<0 ||second_reactant<0)
     {
         printf("Invalid input");
         return 0;
     }
     int total_mass=first_reactant + second_reactant;
     printf("%d",total_mass);
     return 0;
}