Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

var scanner = bufio.NewScanner(os.Stdin)

func nextString() string {
	scanner.Scan()
	return scanner.Text()
}

func nextInt() (int, error) {
	n, err := strconv.Atoi(nextString())
	return n, err
}

func main() {
	scanner.Split(bufio.ScanWords)

	stack := []int{}
	for {
		n, err := nextInt()
		if err != nil {
			break
		}

		if n == 0 { // pop
			fmt.Println(stack[len(stack)-1])
			stack = stack[0:(len(stack) - 1)]
		} else { // push
			stack = append(stack, n)
		}
	}
}

C++: #include <stdio.h>

int train(int array[], int a)
{
	int i;
	for(i=0; i<10; i++)
	{
		if(array[i]==0)
		{
			if(a)
			{
				array[i]=a;
				return 0;
			}
			
			if(i>0 && a==0)
			{
				printf("%d\n", array[i-1]);
				array[i-1]=0;
				return 0;
			}
		}
	}
}
	

int main (void)
{
	int a, trains[10], i;
	
	for(i=0; i<10; i++)
	{
		trains[i]=0;
	}
	
	while(scanf("%d", &a)!=EOF)
	{
		train(trains, a);
	}
	
	return 0;
}

C++: #include <iostream>
#include <vector>
using namespace std;

int main()
{
	vector<int> S;

	int c;
	while(cin>>c)
	{
		if(c==0)
			cout<<S.back()<<endl,
			S.pop_back();
		else
			S.push_back(c);
	}
	return 0;
}

C++: #include <iostream>
using namespace std;

int main(){
	int a[100], i = 0;
	while (true){
		cin >> a[i];
		if (cin.eof()) { break; }
		if (a[i] == 0 ){
			cout << a[i - 1] << endl;
			i--;
		}
		else { i++; }
	}
	return 0;
}

C++: #include<stdio.h>
int main(void)
{
	int car;
	int a[11];
	int i,s;
	i=0;
	while(scanf("%d",&car)!=EOF){
		if(car!=0){
			a[i]=car;
			i++;
		}
		else {
			i--;
			printf("%d\n",a[i]);
		}
	}
	return 0;
}

C++: #define _CRT_SECURE_NO_WARNINGS
#include <vector>
#include <iostream>
using namespace std;

int main() {
	int in;
	vector <int> a;
	while (cin >> in) {
		if (in == 0) {
			cout << a.back();
			a.pop_back();
			/*if (a.size() == 0)
				break;
			else*/
				cout << endl;
		}
		else
			a.push_back(in);
	}
	return 0;
}

C++: #include<iostream>
#include<cstdio>
#include<stack>
using namespace std;

stack<int> sta;

int main(void)
{
  int a;
  while(scanf("%d", &a)!=EOF){
    if(a)
      sta.push(a);
    else{
      cout<<sta.top()<<endl;
      sta.pop();
    }
  }
  return 0;

}

C++: #include <iostream>
#include <stack>
using namespace std;
int main(){
  stack<int>st;
  int a;
  cin >> a;
  st.push(a);
  while(!st.empty()){
    cin >> a;
    if(!a){
      cout << st.top() << endl;
      st.pop();
    }else{
      st.push(a);
    }
  }
  return(0);
}

C++: #include <iostream>
#include <stack>

using namespace std;

int main() {
    stack<int> st;

    for(int n; cin >> n;) {
        if(n == 0) {
            cout << st.top() << endl;
            st.pop();
        }
        else {
            st.push(n);
        }
    }



    return 0;
}

C++: #include<stack>
#include<deque>
#include<iostream>
using namespace std;
int main(){
	int m,n;
	deque<int>deq;
 	while(1){
	    cin>>n;
	    if(n!=0) deq.push_back(n);
	    else {  
                     if(deq.empty()) { continue;}
                     else {     cout<<deq[(int)deq.size()-1]<<endl;
				deq.pop_back();}
            }
	}
        return 0;
}

C++: #include <iostream>
using namespace std;

int main() {
	
	int n , m[12] = {} ;
	
	while( cin >> n ){
		if( cin.eof() ) break ;
		if( n==0 ){
			for( int i=11 ; i>=0 ; i-- ){
				if( m[i] != 0 ){
					cout << m[i] << endl ;
					m[i] = 0 ;
					break ;
				}
			}
		}
		else {
			for( int i=0 ; i<12 ; i++ ){
				if( m[i] == 0 ){
					m[i] = n ;
					break ;
				}
			}
		}
	}
	
	return 0;
}

C++: #include <iostream>
#include <stack>
using namespace std;

int main(){
    stack<int> st;

    int n;

    while(cin >> n){
        if(n == 0){
            cout << st.top() << endl;
            st.pop();
        }else{
            st.push(n);
        }
    }
    return 0;
}

C++: #define _USE_MATH_DEFINES
#include<iostream>
#include<string>
#include<queue>
#include<cmath>
#include<map>
#include<set>
#include<list>
#include<iomanip>
#include<vector>
#include<random>
#include<functional>
#include<algorithm>
#include<stack>
#include<cstdio>
#include<bitset>
#include<unordered_map>
#include<climits>
#include<fstream>
using namespace std;
///////////////////library zone!!!!!!!!!!!!!!!!!!!!!!!!!!!!
typedef long long ll;
typedef long double ld;
#define all(a) (a).begin(),(a).end()
#define EPS (1e-5)
const ll Mod = 1000000007;
const ll mod = 998244353;
struct H {
	ll x, y;
	bool operator<(const H &b) const {
		if (x != b.x) return x < b.x;
		return y < b.y;
	}
	bool operator>(const H &b) const {
		if (x != b.x) return x > b.x;
		return y > b.y;
	}
	bool operator==(const H &b) const { return x == b.x&&y == b.y; }
	bool operator!=(const H &b) const { return (*this) != b; }
};
struct P {
	ll pos, cost;
	bool operator<(const P &b) const { return cost < b.cost; }
	bool operator>(const P &b) const { return cost > b.cost; }
};
struct B {
	ll to, cost;
};
struct E {
	ll from, to, cost;
	bool operator<(const E &b) const { return cost < b.cost; }
	bool operator>(const E &b) const { return cost > b.cost; }
};
template<typename T, typename U>
void chmin(T &a, U b) {
	if (a > b) a = b;
}
template<typename T, typename U>
void chmax(T &a, U b) {
	if (a < b) a = b;
}
template<typename T>
T max_0(T a) {
	if (a < 0) return 0;
	return a;
}
template<typename T>
T min_0(T a) {
	if (a > 0) return 0;
	return a;
}
ll read() {
	ll u;
	ll k = scanf("%lld", &u);
	return u;
}
ll gcd(ll i, ll j) {
	if (i > j) swap(i, j);
	if (i == 0) return j;
	return gcd(j%i, i);
}
ll mod_pow(ll x, ll n, ll p) {
	ll res = 1;
	while (n > 0) {
		if (n & 1) res = res * x % p;
		x = x * x % p;
		n >>= 1;
	}
	return res;
}//x^n%p
const ll Inf = 3023372036854775807;
const int inf = 1500000000;
#define int long long
//----------------------------------------------------
class Vec2 {
public:
	ld x, y;
	Vec2() { x = 0, y = 0; }
	Vec2(ld x, ld y) :x(x), y(y) {}
	ld length() {
		return sqrt(x*x + y * y);
	}
	void normal() {
		ld len = this->length();
		if (len == 0) return;
		x /= len, y /= len;
	}
	Vec2 operator+(Vec2 vec) {
		return Vec2(x + vec.x, y + vec.y);
	}
	Vec2 operator-(Vec2 vec) {
		return Vec2(x - vec.x, y - vec.y);
	}
	Vec2 operator*(int cons) {
		return Vec2(x*cons, y*cons);
	}
	ld operator*(Vec2 vec) {
		return x * vec.x + y * vec.y;
	}
	ld operator%(Vec2 vec) {
		return x * vec.y - y * vec.x;
	}
};
ld dot(Vec2 a, Vec2 b) {
	return a.x*b.x + a.y*b.y;
}
ld cross(Vec2 a, Vec2 b) {
	return a.x*b.y - a.y*b.x;
}
ld areaIntegral(Vec2 a, Vec2 b) {
	return abs(a.x*b.y - a.y*b.x) / 2.0;
}
class Vec3 {
public:
	ld x, y, z;
	Vec3() { x = 0, y = 0, z = 0; }
	Vec3(ld x, ld y, ld z) :x(x), y(y), z(z) {}
	ld length() {
		return sqrt(x*x + y * y + z * z);
	}
	void normal() {
		ld len = this->length();
		if (len == 0) return;
		x /= len, y /= len, z /= len;
	}
	Vec3 operator+(Vec3 vec) {
		return Vec3(x + vec.x, y + vec.y, z + vec.z);
	}
	Vec3 operator-(Vec3 vec) {
		return Vec3(x - vec.x, y - vec.y, z - vec.z);
	}
	Vec3 operator*(int cons) {
		return Vec3(x*cons, y*cons, z*cons);
	}
	ld operator*(Vec3 vec) {
		return x * vec.x + y * vec.y + z * vec.z;
	}
};
ld dot(Vec3 a, Vec3 b) {
	return a.x*b.x + a.y*b.y + a.z*b.z;
}
class Line {
public:
	Vec2 from, to;
	Line(Vec2 from, Vec2 to) :from(from), to(to) {}
};
Line getPerpendicularBisector(Line line) {
	int cx = (line.from.x + line.to.x) / 2, cy = (line.from.y + line.to.y) / 2;
	Vec2 p = Vec2(cx + (line.from.y - line.to.y), cy + (line.to.x - line.from.x));
	return Line(Vec2(cx, cy), p);
}
signed main() {
	int n;
	stack<int>st;
	while (cin >> n) {
		if (n) {
			st.push(n);
		}
		else {
			cout << st.top() << endl;
			st.pop();
		}
	}
}