#include <iostream>
#include <vector>
#include <deque>
#include <algorithm>
#include <numeric>
#include <string>
#include <cstring>
#include <list>
#include <unordered_set>
#include <tuple>
#include <cmath>
#include <limits>
#include <type_traits>
#include <iomanip>
#include <unordered_map>
using namespace std;

using INT = long long;
using UINT = unsigned long long;

UINT gcd(UINT a, UINT b) {
	while (1) {
		if (a < b) swap(a, b);
		if (!b) break;
		a %= b;
	}
	return a;
}

UINT lcm(UINT a, UINT b)
{
	return a * b / gcd(a, b);
}

const UINT mod = 1000000007;
const double pi = 3.141592653589793238462;
const INT intmax = 9223372036854775807;

UINT _PowMod(UINT x, UINT y, UINT _mod)
{
	if (y == 0)
	{
		return 1;
	}
	else if (y == 1)
	{
		return x % _mod;
	}
	else if (y % 2 == 0)
	{
		auto tmp = _PowMod(x, y / 2, _mod);
		return tmp * tmp % _mod;
	}
	else
	{
		auto tmp = _PowMod(x, y / 2, _mod);
		return (tmp * tmp % _mod) * x % _mod;
	}
}


UINT PowMod(UINT x, UINT y)
{
	return _PowMod(x, y, mod);
}

UINT getModInv(UINT N)
{
	return PowMod(N, mod - 2);
}

INT nCrMod(INT start, INT n, INT r)
{
	if (n < r)
	{
		return 0;
	}
	INT a = start;
	for (size_t i = n; i >= n - r + 1; i--)
	{
		a *= i;
		a %= mod;
	}
	for (size_t i = 1; i <= r; i++)
	{
		a *= getModInv(i);
		a %= mod;
	}
	return a;
}

INT nHrMod(INT start, INT n, INT r)
{
	return nCrMod(start, n + r - 1, r);
}

INT _nCrMod(INT start, INT n, INT r)
{
	if (n <= 0)
	{
		return 0;
	}
	return nCrMod(start, n, r);
}

struct uf
{
	vector<INT> p;

	uf(INT n) : p(n)
	{
		for (size_t i = 0; i < n; i++)
		{
			p[i] = i;
		}
	}

	INT rt(INT n)
	{
		return p[n] == n ? n : p[n] = rt(p[n]);
	}

	void un(INT n, INT m)
	{
		p[rt(n)] = p[rt(m)];
	}

	bool eq(INT n, INT m)
	{
		return rt(n) == rt(m);
	}
};

bool lineCol(INT a1x, INT a1y, INT a2x, INT a2y, INT b1x, INT b1y, INT b2x, INT b2y)
{
	auto ta = (b1x - b2x) * (a1y - b1y) + (b1y - b2y) * (b1x - a1x);
	auto tb = (b1x - b2x) * (a2y - b1y) + (b1y - b2y) * (b1x - a2x);
	auto tc = (a1x - a2x) * (b1y - a1y) + (a1y - a2y) * (a1x - b1x);
	auto td = (a1x - a2x) * (b2y - a1y) + (a1y - a2y) * (a1x - b2x);

	return tc * td < 0 && ta * tb < 0;
}

INT powInt(INT a, INT b)
{
	if (b == 0)
	{
		return 1;
	}
	if (b == 1)
	{
		return a;
	}
	INT tmp = powInt(a, b / 2);
	return (b % 2 == 1 ? a * tmp * tmp : tmp * tmp);
}

INT _sMod(string n, INT mod)
{
	INT k = (n[0] - '0') % mod;
	for (size_t i = 1; i < n.length(); i++)
	{
		k *= 10;
		k += (n[i] - '0');
		k %= mod;
	}
	return k;
}

#define forin(v, n)				\
for (size_t i = 0; i < n; i++)	\
{								\
	cin >> v[i];				\
}

#define vec(t, name, n)			vector<t> name(n)
#define vec_(t, name, n, init)	vector<t> name(n, init)

#define vec2(t, name, n, m)			vector<vector<t>> name(n, vector<t>(m))
#define vec2_(t, name, n, m, init)	vector<vector<t>> name(n, vector<t>(m, init))

struct xy
{
	INT x, y;
	xy() :x(0), y(0) {}
	xy(INT _x, INT _y) : x(_x), y(_y) {}
};

int main()
{
	string s;
	cin >> s;
	string a = "";
	for (size_t i = 0; i < s.length(); i++)
	{
		if (s[i] == 'B')
		{
			if (a.length() != 0)
			{
				a.pop_back();
			}
		}
		else
		{
			a.push_back(s[i]);
		}
	}
	cout << a << endl;
	return 0;
}


Measured memory_bytes: 256