void main( )
{
char str[100], queue[100], stack[100], top = -1, front = 0, rear = 0, i;
int IsHuiwen = 1;
gets(str);
for(i = 0; str[i] != '\0'; i++)
{
queue[rear++] = str[i];
stack[++top] = str[i];
}
while(top !== -1 && IsHuiwen)
{
if(stack[top--] != queue[front++])
IsHuiwen = 0;
}
if(IsHuiwen) printf("yes!\n);
else printf("no!\n);
}