c 언어 어디가 잘못된 걸까요?

The purpose of the following program is to check input. It is only supposed to accept a value between 0 and 20, and it should continually ask for input until the correct numbers are entered. However, there is a bug in it.

#include

#define TRUE 1
#define FALSE 0

int main(void)
{
int correct, inputint;

inputint = -1;
correct = FALSE;
while (!correct) {
if (0 < inputint < 20) {
printf("Thank you.\n");
correct = TRUE;
} else {
printf("Enter an integer ");
printf("between 0 and 20: ");
scanf("%d", &inputint);
}
}
return 0;
}

a. Fix the bug so that the program behaves as stated above.

영어책 문제 인데요.
숫자적어야 하는 부분이 나오고 그 뒤에
판별해야 하는건 알겠는데 어디를 어떻게 바꿔야 할지
모르겠습니다.