#include <iostream>
#include <algorithm>
#include<string>
using namespace std;
int top,s[10];
void push(int x){
    s[++top]=x;
}
void pop(){
    top--;
    cout<<s[top+1]<<endl;
}
int main(){
    int num;
    while(1){
        cin>>num;
        if(num==0)
            pop();
        else push(num);
    }
    return 0;
}