#include<stdio.h>
struct area{
    float num1,num2,area;
}s1;
int fun(float *num1, float *num2){
    float area;
    area=2*(*num1+*num2);
}
int main(){
    float l,w;
    scanf("%f%f",& s1.num1,&s1.num2);
    if(l<0 || w<0){
        printf("Invalid input");
        return 0;
    }
    fun(num1,num2);
    printf("%f",s1.area);
    return 0;
}