func_code_string: #include <bits/stdc++.h>   using namespace std;   long long n, m, k, a[100000], b[1000000], i, s, j, x, y;   int main() {     cin >> n >> m;     if (n == m) {       cout <<  0  << endl;       return 0;     }     while (n > 0) {       a[i] = n % 2;       n = n / 2;       i++;     }     while (m > 0) {       b[x] = m % 2;       m = m / 2;       x++;     }     while (a[x] == b[x]) {       x--;     }     y = 1;     for (j = 0; j <= x; j++) {       y *= 2;     }     cout << y - 1 << endl;   }   