1、輸入、輸出必須嚴格按照題目要求進行，包括空格、換行等

2、輸入直到檔案結束應該加上迴圈判斷

while(~scanf("%d", &a))
{
}
while(EOF != scanf("%d", &a))
{
}
while(1 == scanf("%d", &a))
{
}

import java.util.Scanner;
	
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        while(in.hasNext()) {
        	int a = in.nextInt();
        	int b = in.nextInt();
        	System.out.println(a + b);
        }
    }
}