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