Language: C++

/**
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*/
#include <cstring>
#include <vector>
#include <list>
#include <map>
#include <set>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <queue>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <cassert>

#define F first
#define S second
#define endl '\n'
#define deb(x) cout<<#x<<' '<<x<<endl;
#define pb push_back

#ifdef IZI_KATKA
#define int __int64_t
#else
#define int __int64
#endif

const long long MOD = 1e9 + 7;
const long long MAXN = 1e6 + 1;
using namespace std;

typedef long long ll;

long long readInt() {
    bool minus1 = false;
    long long result = 0;
    char ch;
    ch = getchar();
    while (true) {
        if (ch == '-') break;
        if (ch >= '0' && ch <= '9') break;
        ch = getchar();
    }
    if (ch == '-') minus1 = true; else result = ch-'0';
    while (true) {
        ch = getchar();
        if (ch < '0' || ch > '9') break;
        result = result*10 + (ch - '0');
    }
    if (minus1)
        return -result;
    else
        return result;
}

int G(int x, ll l) {
	return (x >> l) & 1;
}

 main() {
	#ifdef IZI_KATKA
	assert(freopen("input", "r", stdin));
    assert(freopen("output", "w", stdout));
    #endif
    ll L = readInt(), R = readInt();
    if (L == R) {
    	return cout << 1, 0;
    }
    ll z = 0;
    for (int i = 60; i >= 0; i--) {
		if (G(L, i) != G(R, i)) {
			z = i;
	    	break;
		} 	
    }
	L %= (1ll << z+1);
	R %= (1ll << z+1);
	ll kek = R ^ (1ll << z);
	ll y = 0;
	for (int i = 0; i <= 60; i++) {
		if ((1ll << i) - 1 >= kek) {
			y = i;
			break;
		}
	}
	ll K = (1ll << y) - 1;
	if (K < L) {
		cout << 2ll * ((1ll << z) - L) + (1ll << y);		
	} else {
		cout << (1ll <<z+1) - L; 
	}
    return 0;
}

Compiler output:
a.cc:35:13: error: '__int64' does not name a type; did you mean '__int64_t'?
   35 | #define int __int64
      |             ^~~~~~~
a.cc:66:1: note: in expansion of macro 'int'
   66 | int G(int x, ll l) {
      | ^~~
a.cc:70:2: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   70 |  main() {
      |  ^~~~
a.cc: In function 'int main()':
a.cc:35:13: error: '__int64' was not declared in this scope; did you mean '__ynf64'?
   35 | #define int __int64
      |             ^~~~~~~
a.cc:80:10: note: in expansion of macro 'int'
   80 |     for (int i = 60; i >= 0; i--) {
      |          ^~~
a.cc:80:22: error: 'i' was not declared in this scope
   80 |     for (int i = 60; i >= 0; i--) {
      |                      ^
a.cc:81:21: error: 'G' was not declared in this scope
   81 |                 if (G(L, i) != G(R, i)) {
      |                     ^
a.cc:35:13: error: '__int64' was not declared in this scope; did you mean '__ynf64'?
   35 | #define int __int64
      |             ^~~~~~~
a.cc:90:14: note: in expansion of macro 'int'
   90 |         for (int i = 0; i <= 60; i++) {
      |              ^~~
a.cc:90:25: error: 'i' was not declared in this scope
   90 |         for (int i = 0; i <= 60; i++) {
      |                         ^