#include <algorithm>
#include <bitset>
#include <cassert>
#include <cctype>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <deque>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>
using namespace std;
using ll = long long;
using ull = unsigned long long;
using pii = pair<int, int>;
using vi = vector<int>;
using vll = vector<ll>;
using vpii = vector<pii>;
#define repn(i, n) for (int i = 1; i <= (int)n; i++)
#define rep(i, n) for (int i = 0; i < (int)n; i++)
#define repr(i, m, n) for (int i = (int)m; i <= (int)n; i++)
#define repd(i, m, n) for (int i = (int)m; i >= (int)n; i--)
#define chmax(a, b) a = max(a, b)
#define chmin(a, b) a = min(a, b)
#ifdef LILYWHITE
	#define eprintf(...) fprintf(stderr, __VA_ARGS__)
#else
	#define eprintf(...) ;
#endif
const int __attribute__((unused)) INF = 0x3f3f3f3f;
template <typename T> inline T rd(T &x) {
	x = 0;
	T neg = 1;
	char c = 0;
	while (c < '0' || c > '9') {
		if (c == '-')
			neg = -1;
		c = getchar();
	}
	while (c >= '0' && c <= '9') {
		x = x * 10 + c - 48;
		c = getchar();
	}
	x *= neg;
	return x;
}
template <typename T, typename... Args> inline void rd(T &x, Args &...args) {
	rd(x);
	rd(args...);
}
#define MULTI
void Main() {
	int n;
	rd(n);
	ll sum = 0, mn = INF, x;
	bool neg = 0;
	rep(i, n) {
		rd(x);
		if (x < 0) neg = 1;
		sum += abs(x);
		chmin(mn, abs(x));
	}
    if (n == 1) {
        cout << x << endl;
        return;
    }
	if (neg) cout << sum << endl;
	else
		cout << sum - 2 * mn << endl;
}
int main() {
#ifdef MULTI
	int T;
	rd(T);
	while (T--)
#endif
		Main();
	return 0;
}