func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 2e6 + 10;   const int MOD = 1e9 + 7;   bool mark[N];   vector<int> ps, corporator[N];   int primeMul[N], primeCnt[N], nthPower[N], b[N], n, k;   int _sum(int, int);   int _mul(int, int);   int _pow(int, int);   void _push(int&, int);   int main() {     cin >> n >> k;     fill(primeMul, primeMul + k + 1, 1);     for (int i = 1; i <= k; i++) {       nthPower[i] = _pow(i, n);       if (i > 1 && !mark[i]) {         for (int j = i; j <= k; j += i) {           mark[j] = true;           primeMul[j] *= i;           primeCnt[j]++;         }       }       if (primeMul[i] == i) ps.push_back(i);     }     for (int i : ps)       for (int j = i; j <= k; j += i) corporator[j].push_back(i);     b[1] = nthPower[1];     int ans = b[1] ^ 1;     for (int i = 2; i <= k; i++) {       b[i] = b[i - 1];       for (int c : corporator[i]) {         int v = _sum(MOD - nthPower[(i - 1) / c], nthPower[i / c]);         _push(b[i], primeCnt[c] & 1 ? MOD - v : v);       }       _push(ans, b[i] ^ i);     }     cout << ans << endl;   }   int _sum(int a, int b) { return a + b - (a + b >= MOD ? MOD : 0); }   int _mul(int a, int b) { return 1LL * a * b % MOD; }   int _pow(int a, int b) {     if (!b) return 1;     int res = _pow(a, b >> 1);     res = _mul(res, res);     if (b & 1) res = _mul(res, a);     return res;   }   void _push(int& a, int b) { a = _sum(a, b); }   