// summation of nth

#include <stdio.h>
#include <string.h>

int main(){
    int n, incriment, sum = 0, i;
    scanf("%d", &n);

    if(n%2 == 0){
        sum = 2;
    }else{
        sum = 1;
    }


    for(i = 1; i<=n; i++){
        sum = sum + 2;
    }

    printf("Summation is : %d", sum);
}