n = int(input())
sum = 0
for i in range(n):
sum+=(i+1)*(n-i)-i
print(sum)#include "bits/stdc++.h"
using namespace std;
using ll = long long;
const ll N = 1e5 + 7, inf = LLONG_MAX;
#define fastik ios_base::sync_with_stdio(false); cin.tie(nullptr);
#define ff first
#define ss second
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
typedef vector<ll> vec;
typedef vector<vec> vec_;
void solve(){ fastik;
ll n, m = 0; cin >> n;
for(ll i = 0; i < n; i++) m += (n - i + ((n - i - 1) * i));
cout << m;
}
signed main (){ fastik;
ll test = 1; //cin >> test;
while(test--) solve(), cout << '\n';
cin.get();
return 0;
}
// - 32 !- 33 "- 34 #- 35 $- 36 %- 37 &- 38 '- 39 (- 40 )- 41 *- 42 +- 43 ,- 44 -- 45 .- 46 /- 47
// 0- 48 1- 49 2- 50 3- 51 4- 52 5- 53 6- 54 7- 55 8- 56 9- 57 :- 58 ;- 59 <- 60 =- 61 >- 62 ?- 63
// @- 64 A- 65 B- 66 C- 67 D- 68 E- 69 F- 70 G- 71 H- 72 I- 73 J- 74 K- 75 L- 76 M- 77 N- 78 O- 79
// P- 80 Q- 81 R- 82 S- 83 T- 84 U- 85 V- 86 W- 87 X- 88 Y- 89 Z- 90 [- 91 \- 92 ]- 93 ^- 94 _- 95
// `- 96 a- 97 b- 98 c- 99 d-100 e-101 f-102 g-103 h-104 i-105 j-106 k-107 l-108 m-109 n-110 o-111
// p-112 q-113 r-114 s-115 t-116 u-117 v-118 w-119 x-120 y-121 z-122 {-123 |-124 }-125 ~-126 -127 1832. Check if the Sentence Is Pangram | 1678. Goal Parser Interpretation |
1389. Create Target Array in the Given Order | 1313. Decompress Run-Length Encoded List |
1281. Subtract the Product and Sum of Digits of an Integer | 1342. Number of Steps to Reduce a Number to Zero |
1528. Shuffle String | 1365. How Many Numbers Are Smaller Than the Current Number |
771. Jewels and Stones | 1512. Number of Good Pairs |
672. Richest Customer Wealth | 1470. Shuffle the Array |
1431. Kids With the Greatest Number of Candies | 1480. Running Sum of 1d Array |
682. Baseball Game | 496. Next Greater Element I |
232. Implement Queue using Stacks | 844. Backspace String Compare |
20. Valid Parentheses | 746. Min Cost Climbing Stairs |
392. Is Subsequence | 70. Climbing Stairs |
53. Maximum Subarray | 1527A. And Then There Were K |
1689. Partitioning Into Minimum Number Of Deci-Binary Numbers | 318. Maximum Product of Word Lengths |
448. Find All Numbers Disappeared in an Array | 1155. Number of Dice Rolls With Target Sum |
415. Add Strings | 22. Generate Parentheses |