/*
#include <stdio.h>
int stack[1000]={};
int top=-1;
void push(int d)
{
top++;
stack[top]=d;
}
int pop()
{
if(top==-1)
printf("pop할 정수라 없습니다.");
else
return stack[top--];
}
void view()
{
printf("stack = [ ");
for(int i=0;i<=top;i++)
printf("%d ",stack[i]);
printf("] top = %d \n",top);
}
int main()
{
int c,num;
while(1)
{
printf("----------stack programmmm----------\n");
printf("1. push 2.pop 3. view >> ");
scanf("%d",&c);
if(c==1)
{
printf("push할 정수를 입력하세요. >> ");
scanf("%d",&num);
push(num);
}
if(c==2)
printf("%d를 pop 하였습니다.\n",pop());
if(c==3)
view();
}
return 0;
}
*/
/*#include <stdio.h>
#include <string.h>
char stack[200]={};
int top=-1;
void push(char d)
{
top++;
stack[top]=d;
}
char pop()
{
if(top!=-1)
return stack[top--];
}
int main()
{
int n,i,num[202]={};
scanf("%d",&n);
for(i=0;i<n;i++)
scanf("%1d",&num[i]);
for(i=n-1;i>=0;i--)
{
push(num[i]+48);
if((n-i)%3==0&&i!=0)
push(',');
}
while(1)
{
printf("%c",pop());
if(top==-1)
break;
}
return 0;
}*/
#include <stdio.h>
int stack[200]={},top=-1;
void push(int d)
{
top++;
stack[top]=d;
}
void pop()
{
if(top!=-1)
top--;
}
void topf()
{
if(top==-1)
printf("-1\n");
else
printf("%d\n",stack[top]);
}
void size()
{
printf("%d\n",top+1);
}
void empty()
{
if(top==-1)
printf("true\n");
else
printf("false\n");
}
int main()
{
int j,i,n,k=0;
char stl[22]={};
scanf("%d\n",&n);
for(i=0;i<n;i++)
{
gets(stl);
if(stl[3]=='h')
{
for(j=6;stl[j]!=' ';j++)
k=k*10+stl[j]-'0';
//printf("\n push data is %d\n",k);
push(k);
k=0;
}
else if(stl[2]=='z')
size();
else if(stl[4]=='y')
empty();
else if(stl[0]=='t')
topf();
else if(stl[0]=='p'&&stl[1]=='o')
pop();
}
return 0;
}