func_code_string: #include <bits/stdc++.h>   #pragma GCC optimize( O3 )   using namespace std;   long long n;   bool valid(long long x) {     long long a = 0, b = 0;     long long r = n;     while (r) {       a += min(r, x);       r -= min(r, x);       b += r / 10;       r -= r / 10;     }     return a >= b;   }   signed main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     long long seed;     asm( rdtsc  :  =A (seed));     srand(seed);     cin >> n;     long long lo = 0, hi = n;     while (lo + 1 < hi) {       long long mid = (lo + hi) / 2;       if (valid(mid))         hi = mid;       else         lo = mid;     }     cout << lo + 1 <<   n ;   }   