#include<stdio.h>
int main() {
int first_reaction;
int second_reaction;
    scanf("%d",&first_reaction);
    scanf("%d",&second_reaction);
    if (first_reaction<=0 || second_reaction<=0) {
        printf("Invalid input");
    }else {
        int total_mass = first_reaction + second_reaction;
        printf("Invalid input");
    }
    else {
        int total_mass = first_reaction + second_reaction;
        printf("%d",total_mass);
        return 0;
    }
}