#include<cstdio>
#define R register int
int T,a,b;
namespace FastIO {
const int SIZE = 1 << 16;
char buf[SIZE], str[64];
int l = SIZE, r = SIZE;
int read(char *s) {
while (r) {
for (; l < r && buf[l] <= ' '; l++);
if (l < r) break;
l = 0, r = int(fread(buf, 1, SIZE, stdin));
}
int cur = 0;
while (r) {
for (; l < r && buf[l] > ' '; l++) s[cur++] = buf[l];
if (l < r) break;
l = 0, r = int(fread(buf, 1, SIZE, stdin));
}
s[cur] = '\0';
return cur;
}
template<typename type>
bool read(type &x, R len = 0, R cur = 0, bool flag = false) {
if (!(len = read(str))) return false;
if (str[cur] == '-') flag = true, cur++;
for (x = 0; cur < len; cur++) x = x * 10 + str[cur] - '0';
if (flag) x = -x;
return true;
}
template <typename type>
type read(R len = 0, R cur = 0, bool flag = false, type x = 0) {
if (!(len = read(str))) return false;
if (str[cur] == '-') flag = true, cur++;
for (x = 0; cur < len; cur++) x = x * 10 + str[cur] - '0';
return flag ? -x : x;
}
} using FastIO::read;
int plus(R a,R b) {
if(!a || !b) return a|b;
return ((a&b) << 1,a ^ b);
}
int main() {
read(T);
for(R i = 1;i <= T;++i) {
read(a),read(b);
printf("%d\n",plus(a,b));
}
return 0;
}