#include <stdio.h>

int main()
{
    ;
}

/* this handles EOF as wall */
int buffc = -1;

char getch()
{
    char temp;
    return (buffc < 0) ? getchar() : (temp = buffc, buffc = -1, temp);
}

void ungetch(int c)
{
    if (buffc >= 0)
        printf("warning: overriding character buffer\n");
    buffc = c;
}