#include <stdio.h>
#include <stdlib.h>
#include
using namespace std;
typedef char DataType;
typedef struct Stack {
DataType* a;
int top;
}Stack;
void StackInit (Stack* S)
{
S->a = NULL;
S->top = 0;
}
void StackPush (Stack* S, DataType x)
{
if (S->a == NULL)
S->a = (DataType*)malloc(10000*sizeof(DataType));
S->a[S->top] = x;
S->top ++;
}
DataType StackTop (Stack* S)
{
if (S->top != 0)
return S->a[S->top - 1];
}
int main ()
{
Stack st;
DataType c;
StackInit (&st);
cin >> c;
StackPush (&st, c);
cout << StackTop (&st));
return 0;
}