该段代码为何在hdu1000无法通过

[MessiahJK]

题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=1000
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.InputMismatchException;

public class Main {
static InputStream is;
PrintWriter out;
String INPUT = "1 1 3 4";

void solve() {
while (true) {
if(eof())break;
long a = nl(), b = nl();
out.println(a + b);
}
}

void run() throws Exception {
// is = oj ? System.in : new ByteArrayInputStream(INPUT.getBytes());
is = System.in;
out = new PrintWriter(System.out);
long s = System.currentTimeMillis();
solve();
out.flush();
// tr(System.currentTimeMillis() - s + "ms");
}

public static void main(String[] args) throws Exception {
new Main().run();
}

private static byte[] inbuf = new byte[1024];
public static int lenbuf = 0;
public static int ptrbuf = 0;
private static boolean eof() {
if (lenbuf == -1)
return true;
int lptr = ptrbuf;
while (lptr < lenbuf)
if (!isSpaceChar(inbuf[lptr++]))
return false;
try {
is.mark(1000);
while (true) {
int b = is.read();
if (b == -1) {
is.reset();
return true;
} else if (!isSpaceChar(b)) {
is.reset();
return false;
}
}
} catch (IOException e) {
return true;
}
}

private int readByte() {
if (lenbuf == -1)
throw new InputMismatchException();
if (ptrbuf >= lenbuf) {
ptrbuf = 0;
try {
lenbuf = is.read(inbuf);
} catch (IOException e) {
throw new InputMismatchException();
}
if (lenbuf <= 0)
return -1;
}
return inbuf[ptrbuf++];
}

private static boolean isSpaceChar(int c) {
return !(c >= 33 && c <= 126);
}

private int skip() {
int b;
while ((b = readByte()) != -1 && isSpaceChar(b))
;
return b;
}

private double nd() {
return Double.parseDouble(ns());
}

private char nc() {
return (char) skip();
}

private String ns() {
int b = skip();
StringBuilder sb = new StringBuilder();
while (!(isSpaceChar(b))) { // when nextLine, (isSpaceChar(b) && b != ' ')
sb.appendCodePoint(b);
b = readByte();
}
return sb.toString();
}

private char[] ns(int n) {
char[] buf = new char[n];
int b = skip(), p = 0;
while (p < n && !(isSpaceChar(b))) {
buf[p++] = (char) b;
b = readByte();
}
return n == p ? buf : Arrays.copyOf(buf, p);
}

private char[][] nm(int n, int m) {
char[][] map = new char[n][];
for (int i = 0; i < n; i++)
map[i] = ns(m);
return map;
}

private int[] na(int n) {
int[] a = new int[n];
for (int i = 0; i < n; i++)
a[i] = ni();
return a;
}

private int ni() {
int num = 0, b;
boolean minus = false;
while ((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'))
;
if (b == '-') {
minus = true;
b = readByte();
}

while (true) {
if (b >= '0' && b <= '9') {
num = num * 10 + (b - '0');
} else {
return minus ? -num : num;
}
b = readByte();
}
}

private long nl() {
long num = 0;
int b;
boolean minus = false;
while ((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'))
;
if (b == '-') {
minus = true;
b = readByte();
}

while (true) {
if (b >= '0' && b <= '9') {
num = num * 10 + (b - '0');
} else {
return minus ? -num : num;
}
b = readByte();
}
}

private boolean oj = System.getProperty("ONLINE_JUDGE") != null;

private void tr(Object... o) {
if (!oj)
System.out.println(Arrays.deepToString(o));
}
}