Language: C++


// <------------- Template -----------------------> //

/*
#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
#pragma GCC optimization("unroll-loops")
*/

#pragma optimization_level 3   									//Comment optimisations for an interatcive problem - use endl
#pragma GCC optimize("Ofast,no-stack-protector,unroll-loops,fast-math,O3")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")

#include<bits/stdc++.h>
using namespace std;

#define fastio 			ios::sync_with_stdio(0);	cin.tie(0); cout.tie(0);  cout<<fixed;  cout<<setprecision(12);
#define randomINT 		mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());
#define	newl 			cout<<"\n"
#define DISP(as)		for(auto it : as) cout<<it<<" ";newl;
#define all(x)         	(x).begin(),(x).end()
#define mset(x,val)    	memset(x,val,sizeof(x))
#define newl           	cout<<"\n"
#define pb             	push_back
#define mp             	make_pair
#define f 				first
#define s 				second
#define dline          cerr<<"///REACHED///\n";
#define deb1(x)        cerr<<#x<<" = "<<x<<'\n';
#define deb2(x,y)      cerr<<'['<<#x<<','<<#y<<"] = "<<'['<<x<<','<<y<<']'<<'\n';
#define deb3(x,y,z)    cerr<<'['<<#x<<','<<#y<<','<<#z<<"] = "<<'['<<x<<','<<y<<','<<z<<']'<<'\n';
#define N 1000000007 // prime modulo value 

typedef long long 				ll;
typedef long double 			ld;
typedef vector<ll> 				vll;
typedef pair<ll , ll> 			pll;
typedef pair<ld, ld> 			pld;
typedef unordered_map<ll, ll> 	um;
typedef vector<pll> 			vpll;

const ll 	MAX5 	= 	1e+5 + 7;
const ll 	MAX7 	= 	1e+7 + 7;
const ll 	MAXN 	= 	MAX7;
const ll   	INF   	=  	0x7f7f7f7f7f7f7f7f;
const int  	INFi 	=  	0x7f7f7f7f;
const ll 	MOD		=  	1e+9 + 7;

vll adj[MAXN]; ll visit[MAXN] = {};
int dx8[] = {0, 1, 1, 1, 0, -1, -1, -1}, dy8[] = {1, 1, 0, -1, -1, -1, 0, 1};
int dx4[] = {0, 1, 0, -1}, dy4[] = {1, 0, -1, 0};

// <------------- Declare Variables Here ------------> //

ll t = 1;
ll n, k;
string s;

// <------------- Implement Functions Here ----------> //


long long exponentiation(long long base,
                         long long exp)
{
	if (exp == 0)
		return 1;

	if (exp == 1)
		return base % N;

	long long t = exponentiation(base, exp / 2);
	t = (t * t) % N;

	// if exponent is even value
	if (exp % 2 == 0)
		return t;

	// if exponent is odd value
	else
		return ((base % N) * t) % N;
}

// <------------- Start of main() -------------------> //

void MAIN() {
	cin >> n >> k;
	ll ans = 0;
	ll cnt[k+5];
	mset(cnt,0);
	for (ll i = k; i > 0; i--) {
		cnt[i] = exponentiation(k / i, n);
		for (ll j = 2 * i; j <= k; j += i) {
			cnt[i] = (cnt[i] - cnt[j] + MOD) % MOD;
		}
		ans = (ans + i*cnt[i])%MOD;
	}
	cout<<ans;newl;
}

int main() {
	fastio; randomINT;
	//cin>>t;
	while (t--) {
		MAIN();
	}
	return 0;
}


Compiler output:
In file included from /usr/include/c++/14/string:43,
                 from /usr/include/c++/14/bitset:52,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:52,
                 from a.cc:14:
/usr/include/c++/14/bits/allocator.h: In destructor 'std::__cxx11::basic_string<char>::_Alloc_hider::~_Alloc_hider()':
/usr/include/c++/14/bits/allocator.h:182:7: error: inlining failed in call to 'always_inline' 'std::allocator< <template-parameter-1-1> >::~allocator() noexcept [with _Tp = char]': target specific option mismatch
  182 |       ~allocator() _GLIBCXX_NOTHROW { }
      |       ^
In file included from /usr/include/c++/14/string:54:
/usr/include/c++/14/bits/basic_string.h:186:14: note: called from here
  186 |       struct _Alloc_hider : allocator_type // TODO check __is_final
      |              ^~~~~~~~~~~~