#include <conio.h>
#include <iostream>
#include <ctype.h>

using namespace std;

int main() {
	int chisodau, chisocuoi, sokwh;
	long tientra;
	char traloi;
	do {
		cout<<"\nNhap chi so dien dau thang: ";
		cin>>chisodau;
		cout<<"Nhap chi so dien cuoi thang: ";
		cin>>chisocuoi;
		if (chisocuoi > chisodau && chisodau >= 0) {
			sokwh = chisocuoi - chisodau;
			if (sokwh <= 100)
				tientra=sokwh*1000L; //hang kieu long
			else if (sokwh<=200)
				tientra=100*1000L + (sokwh-100)*1500L;
			else
				tientra = 100 * 1000L + 100 * 1500L + (sokwh - 200) * 3000L;
			cout<<"So tien phai tra: "<<tientra;
		} else cout<<"Du lieu khong hop le";
		cout<<"\nBan co tiep tuc voi gia dinh khac khong? (C/K): ";
		traloi = getche();
	} while (toupper(traloi) == 'C');
	getch();
	return 0;
}