Codeforces Round #650 (Div. 3) (A-D)

[传送门]

A. Short Substrings

Alice guesses the strings that Bob made for her.

At first, Bob came up with the secret string a consisting of lowercase English letters. The string a has a length of 2 or more characters. Then, from string a he builds a new string b and offers Alice the string b so that she can guess the string a.

Bob builds b from a as follows: he writes all the substrings of length 2 of the string a in the order from left to right, and then joins them in the same order into the string b.

For example, if Bob came up with the string a=“abac”, then all the substrings of length 2 of the string a are: “ab”, “ba”, “ac”. Therefore, the string b=“abbaac”.

You are given the string b. Help Alice to guess the string a that Bob came up with. It is guaranteed that b was built according to the algorithm given above. It can be proved that the answer to the problem is unique.

Input

The first line contains a single positive integer t (1≤t≤1000) — the number of test cases in the test. Then t test cases follow.

Each test case consists of one line in which the string b is written, consisting of lowercase English letters (2≤|b|≤100) — the string Bob came up with, where |b| is the length of the string b. It is guaranteed that b was built according to the algorithm given above.

Output

Output t answers to test cases. Each answer is the secret string a, consisting of lowercase English letters, that Bob came up with.

Example

input

4
abbaac
ac
bccddaaf
zzzzzzzzzz

output

abac
ac
bcdaf
zzzzzz

my Accept code

#include <algorithm>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>

#define ll long long
#define db double
#define inf INT_MAX
#define s(a, n) memset(a, n, sizeof(a))
#define g(a, max) fgets(a, max, stdin)
#define debug(a) cout << '#' << a << '#' << endl

using namespace std;
bool fi = true;
const unsigned long long MOD = 1e9 + 7;

int main() {
   
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n;
    cin >> n;
    for (int i = 0; i < n; i++) {
   
        string a;
        cin >> a;
        string ans = "";
        for (int j = 0; j < a.size(); j += 2) {
   
            ans = ans + a[j];
        }
        ans += a[a.size() - 1];
        cout << ans << endl;
    }
}

B. Even Array

You are given an array a[0…n−1] of length n which consists of non-negative integers. Note that array indices start from zero.

An array is called good if the parity of each index matches the parity of the element at that index. More formally, an array is good if for all i (0≤i≤n−1) the equality imod2=a[i]mod2 holds, where xmod2 is the remainder of dividing x by 2.

For example, the arrays [0,5,2,1] and [0,17,0,3] are good, and the array [2,4,6,7] is bad, because for i=1, the parities of i and a[i] are different: imod2=1mod2=1, but a[i]mod2=4mod2=0.

In one move, you can take any two elements of the array and swap them (these elements are not necessarily adjacent).

Find the minimum number of moves in which you can make the array a good, or say that this is not possible.

Input

The first line contains a single integer t (1≤t≤1000) — the number of test cases in the test. Then t test cases follow.

Each test case starts with a line containing an integer n (1≤n≤40) — the length of the array a.

The next line contains n integers a0,a1,…,an−1 (0≤ai≤1000) — the initial array.

Output

For each test case, output a single integer — the minimum number of moves to make the given array a good, or -1 if this is not possible.