#include<stdio.h>
int top=-1;
int size=5;
int arr[size];
int push(int val){
    if(top==size-1){
        printf("Stack Oveflow");
    }else{
        arr[++top]=val;
    }
}
int pop(){
    if(top==-1){
        printf("Stack Underflow");
    }else{
        return top--;
    }
}
void display(){
    for(int i=size-1;i<size;i--){
        printf("%d ",arr[i]);
    }
}
void peek(){
    return arr[top];
}
int main(){
    // int size;
    // scanf("%d",&size);
    for(int i=0;i<size;i++){
        scanf("%s",num);
        if(strcmp(num,"PUSH")){
            push();
        }else if(strcmp(num,"PUSH")){
            pop();
        }else{
            display();
        }
    }
}