#include <stdio.h>
#include <stdint.h>
#include <string.h>
#define MAX 10
int tos=-1;
void push(int num,int *arr){
if (tos == MAX-1)
printf("Stack Overflow\n");
else
arr[++tos]=num;
}
void pop(int *arr){
if (tos==-1)
printf("Stack Underflow\n");
else{
printf("%d\n",arr[tos--]);
}
}
void process_stack(int n) {
// Your logic here
int stack[MAX]={0},num;
for (int i=0;i<n;i++){
char str[4]={0};
scanf("%s",str);
if (!strcmp(str,"push")){
scanf("%d",&num);
push(num,stack);
}
else
pop(stack);
}
}
int main() {
int n;
scanf("%d", &n);
getchar(); // Consume newline after number
process_stack(n);
return 0;
}