#include<stdio.h>
int main(){
    int r1,r2;
    if(scanf("%d %d",&r1,&r2)!=2 ){
        printf("Invalid Input");
        return0;
    }
    if(r1 < 0 || r2 < 0)
    printf("Invalid input");
    else
    printf("%d",r1+r2);
    return 0;
}