#include<stdio.h>
#include<conio.h>
int main()
{
int i, n;
int max;
max = 0;
do
{
printf("\nNhap n: ");
scanf("%d", &n);
}while(n < 0 && printf("\nLoi: n >= 0 !"));
if(n == 0)
max = 0;
do
{
i = n % 10;
if(i > max)
{
max = i;
}
}while(n /= 10);
printf("\nChu so lon nhat la %d", max);
getch();
return 0;
}