#include <math.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <assert.h>
#include <limits.h>
#include <stdbool.h>

long int sumOfGroup(int k) {
    // Return the sum of the elements of the k'th group.
    int n = 1;
    int i,j;
    int index = 0;
    int *sum = (int*)calloc(sizeof(int),k);
    
    sum[index] = n;
    index++;
    for(i = 0; i < k; i++)
    {
        if(i  == 0 )
         continue;
                
            for(j = 0; j < i+1; j++)
             {
              n += 2;
              sum[index] += n;
             }  
        index++;
        
    }
 return sum[index-1];

}

int main() {
    int k; 
    scanf("%i", &k);
    long int answer = sumOfGroup(k);
    printf("%ld\n", answer);
    return 0;
}