#include<numeric>
#include<random>
#include <iostream>
#include <queue>
#include <stack>
#include <bitset>
#include <algorithm>
#include <cassert>
#include <chrono>
#include <iomanip>
#include <set>
#include <map>
#include <string>
#include <complex>
#include<vector>
#include<unordered_map>
#include<unordered_set>
#include<cmath>

#ifdef __GNUC__
#pragma GCC target ("avx2")
#pragma GCC optimize ("O3")
#pragma GCC optimize ("unroll-loops")
#endif
using namespace std;
using ll = int64_t;
using vi = vector<int>;
using vvi = vector<vi>;
using vll = vector<ll>;
using namespace std;
bool c = 1;
inline ll msb(ll x) {
    if (!x)
        return -1;
#ifdef _MSC_VER
    unsigned long ret;
    _BitScanReverse64(&ret, x);
    return ret;
#endif
#ifdef __GNUC__
    int ret = 63 - __builtin_clzll(x);
    return ret;
#endif
    return 0;
}

void nine11(int tst) {
    int x, y; cin >> x >> y;
    int ans = -1;
    for (int i = 1; i <= 100; i++) {
        if (i%y== 0 || i % x == 0)
            continue;
        ans = i;
    }
    cout << ans << '\n';    
}
signed main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0), cout.tie(0);
    int t = 1; cin >> t;
    for (int i = 1; i <= t && c; i++) {
        nine11(i);
    }
    cout.flush();
    return 0;
}