20260305
/*
#include <stdio.h>
int stack[201]={};
int ttop=-1;
void push(int a)
{
ttop++;
stack[ttop] = a;
}
void pop()
{
if(ttop > -1) ttop--;
}
void top()
{
if(ttop == -1)
{
printf("-1\n");
}
else
{
printf("%d\n", stack[ttop]);
}
}
void size()
{
printf("%d\n", ttop+1);
}
void empty()
{
if(ttop == -1)
{
printf("true\n");
}
else
{
printf("false\n");
}
}
int main()
{
int n;
char c[20]={};
scanf("%d", &n);
getchar();
for(int i=0; i<n; i++)
{
gets(c);
int x = 0;
if(c[0]=='p' && c[1]=='u')
{
for(int j=6; c[j]!=' '; j++)
{
x = x * 10 + (c[j] - '0');
}
push(x);
}
else if(c[0]=='p')
{
pop();
}
else if(c[0]=='t')
{
top();
}
else if(c[0]=='s')
{
size();
}
else
{
empty();
}
}
return 0;
}
*/
/*
#include <stdio.h>
int queue[201] = {};
int ffront = -1;
int bback = -1;
void push(int a)
{
bback++;
queue[bback] = a;
}
void pop()
{
if(bback - ffront != 0) ffront++;
}
void front()
{
if(bback - ffront != 0) printf("%d\n", queue[ffront+1]);
else printf("-1\n");
}
void back()
{
if(bback - ffront != 0) printf("%d\n", queue[bback]);
else printf("-1\n");
}
void size()
{
printf("%d\n", bback - ffront);
}
void empty()
{
if(bback - ffront == 0)
{
printf("true\n");
}
else
{
printf("false\n");
}
}
int main()
{
int n;
char c[20] = {};
scanf("%d", &n);
getchar();
for(int i=0; i<n; i++)
{
gets(c);
int x = 0;
if(c[0]=='p' && c[1]=='u')
{
for(int j=6; c[j]!=' '; j++)
{
x = x * 10 + (c[j] - '0');
}
push(x);
}
else if(c[0]=='p')
{
pop();
}
else if(c[0]=='f')
{
front();
}
else if(c[0]=='b')
{
back();
}
else if(c[0]=='s')
{
size();
}
else if(c[0]=='e')
{
empty();
}
}
return 0;
}
*/
#include <stdio.h>
#include <stdlib.h>
typedef struct NODE
{
int data;
struct NODE *next;
}node;
node* make_node(int d)
{
node *tmp = (node*)malloc(sizeof(node));
tmp->data = d;
tmp->next = NULL;
return tmp;
}
node* make_head()
{
node *tmp = (node*)malloc(sizeof(node));
tmp->next = NULL;
return tmp;
}
void push(int a)
{
node* new_node = make_node(a);
new_node->next =
}
void pop()
{
}
void top()
{
}
void size()
{
}
void empty()
{
}
int main()
{
int n;
char c[20] = {};
scanf("%d", &n);
getchar();
for(int i=0; i<n; i++)
{
gets(c);
int x = 0;
if(c[0]=='p' && c[1]=='u')
{
for(int j=6; c[j]!=' '; j++)
{
x = x * 10 + (c[j] - '0');
}
push(x);
}
else if(c[0]=='p')
{
pop();
}
else if(c[0]=='t')
{
top();
}
else if(c[0]=='s')
{
size();
}
else if(c[0]=='e')
{
empty();
}
}
return 0;
}