#include <stdio.h>
#include <string.h>
#include <ctype.h>
#define MAX 100

int main(){
	char hoten[MAX];
	char email[MAX] = "";
	char mssv[7];
	printf("Nhap ho ten sinh vien: ");
	gets(hoten);
	printf("Nhap ma so sinh vien: ");
	gets(mssv);
	printf("Ho ten sinh vien la: %s\n", hoten);
	int l = strlen(hoten);
	int k = strlen(mssv);
	int i, m;
	int j = 0; //Bien dem vi tri cua chuoi email 
	
	//Gan i tai diem co khoang trang bang cach dem nguoc chuoi HoTen
	for(i = l - 1; i > 0; i--)			
		if(hoten[i] == ' ') break;			
	
	//Them chuoi tu vi tri i + 1(i la vi tri tai khoang trang) cua chuoi HoTen tro di vao chuoi email.
	for(m = i + 1; m < l; m++)
		email[j++] = hoten[m];
		
	//Them dau cham va chu cai dau tien vao chuoi email
	email[j++] = '.';
	email[j++] = hoten[0];
	
	//Them chu cai dau tien cua chuoi HoTen sau khoang trang vao email
	for(m = 0; m < i; m++){
		if(hoten[m] == ' '){
			m++;
			email[j++] = hoten[m];
		}
	}
		
	//Them 4 chu so cuoi mssv vao email
	for(int s = 3; s < k; s++)
		email[j++] = mssv[s];
		
	//Chuyen tat ca chu cai thanh chu thuong trong chuoi email
	for(int t = 0; t <= strlen(email); t++)
		email[t] = tolower(email[t]);
		
	email[j] = 0;
	printf("Email: %s@sinhvien.hoasen.edu.vn", email);
	return 0;
}