#include<stdio.h>
#include<ctype>
int main()
{
    int a,b,c;
    scanf("%d",&a);
    scanf("%d",&b);
    if(a<0 || b<0 || isalpha = a || isalpha = b)
    printf("Invalid input");
    else 
    printf("%d",a+b);
    return 0;
}