#include <stdio.h>
#include <conio.h>
#include <math.h>
int main()
{
	
	//nhap VAO SO XE BAO GOM 5 CHU SO TINH SO NUT 
	
	int soxe;

	printf("\nhay nhap vao so xe : ");
	scanf("%d",&soxe);
    
	int sochuso;
	sochuso = log10 ((float)soxe) + 1;
	//printf("\nso %d co %d chu so !",soxe,sochuso);

	/*
	12345=>1 + 2 + 3 + 4 + 5 = 15 => 5 nut 
	12345 % 10 = 5
	12345 / 10 = 1234
	*/
	int sonut = 0;

	sonut += soxe % 10;// lan 1 
	soxe /= 10; // bo so cuoi

	sonut += soxe % 10;// lan 2
	soxe /= 10; // bo so cuoi

	sonut += soxe % 10;// lan 3
	soxe /= 10; // bo so cuoi

	sonut += soxe % 10;// lan 4 
	soxe /= 10; // bo so cuoi

	sonut += soxe % 10;// lan 5
	soxe /= 10; // bo so cuoi

	sonut += soxe;

	sonut %= 10; // lay hang don vi 

	sochuso == 5 ? printf("\nso nut = %d",sonut) : printf("xin hay nhap dung 5 chu so cam on");


   getch();
   return 0;


}