int main(){
    int reactant1, reactant2;
    if (scanf("%d",&reactant1) !=1){
        printf("Invalid input");
        return 0;
    }
    if (scanf("%d",&reactant2) !=1){
        printf("Invalid input");
        return 0;
    }
    if (reactant1 < 0 || reactant1 ||r ctant1 < -1000 || reactant1 > 1000 || reactant2 < -1000 || reactant2 > 1000){
        printf("Invalid input");
        return 0;
    }
    int totalMass = reactant1 + reactant2;
    printf("%d",totalMass);
    return 0;
}