#include using namespace std; //#define int long long typedef long long ll; typedef unsigned long long ul; typedef unsigned int ui; const ll mod = 1000000007; const ll INF = mod * mod; const int INF_N = 1e+9; typedef pair P; #define stop char nyaa;cin>>nyaa; #define rep(i,n) for(int i=0;i=0;i--) #define Rep(i,sta,n) for(int i=sta;i=1;i--) #define Rep1(i,sta,n) for(int i=sta;i<=n;i++) #define all(v) (v).begin(),(v).end() typedef pair LP; typedef long double ld; typedef pair LDP; const ld eps = 1e-12; const ld pi = acos(-1.0); //typedef vector> mat; typedef vector vec; //繰り返し二乗法 ll mod_pow(ll a, ll n, ll m) { ll res = 1; while (n) { if (n & 1)res = res * a%m; a = a * a%m; n >>= 1; } return res; } struct modint { ll n; modint() :n(0) { ; } modint(ll m) :n(m) { if (n >= mod)n %= mod; else if (n < 0)n = (n%mod + mod) % mod; } operator int() { return n; } }; bool operator==(modint a, modint b) { return a.n == b.n; } modint operator+=(modint &a, modint b) { a.n += b.n; if (a.n >= mod)a.n -= mod; return a; } modint operator-=(modint &a, modint b) { a.n -= b.n; if (a.n < 0)a.n += mod; return a; } modint operator*=(modint &a, modint b) { a.n = ((ll)a.n*b.n) % mod; return a; } modint operator+(modint a, modint b) { return a += b; } modint operator-(modint a, modint b) { return a -= b; } modint operator*(modint a, modint b) { return a *= b; } modint operator^(modint a, int n) { if (n == 0)return modint(1); modint res = (a*a) ^ (n / 2); if (n % 2)res = res * a; return res; } //逆元(Eucledean algorithm) ll inv(ll a, ll p) { return (a == 1 ? 1 : (1 - p * inv(p%a, a)) / a + p); } modint operator/(modint a, modint b) { return a * modint(inv(b, mod)); } const int max_n = 1 << 18; modint fact[max_n], factinv[max_n]; void init_f() { fact[0] = modint(1); for (int i = 0; i < max_n - 1; i++) { fact[i + 1] = fact[i] * modint(i + 1); } factinv[max_n - 1] = modint(1) / fact[max_n - 1]; for (int i = max_n - 2; i >= 0; i--) { factinv[i] = factinv[i + 1] * modint(i + 1); } } modint comb(int a, int b) { if (a < 0 || b < 0 || a < b)return 0; return fact[a] * factinv[b] * factinv[a - b]; } using mP = pair; int dx[4] = { 0,1,0,-1 }; int dy[4] = { 1,0,-1,0 }; void solve() { int N; cin >> N; vec a(N); ll res = INF; int num = 0; rep(i, N){ cin >> a[i]; if(res > a[i]){ res = a[i]; num = i; } } vec mi(N), rmi(N); rep(i, N){ if(i == 0) mi[i] = a[i]; else { mi[i] = min(mi[i-1], a[i]); } } per(i, N){ if(i == N-1) rmi[i] = a[i]; else{ rmi[i] = min(rmi[i+1], a[i]); } } ll res1 = INF; Rep(i, 1, N-1){ if(mi[i-1] < a[i] && a[i] > rmi[i+1]) res1 = min(res1, (ll)mi[i-1]+a[i]+rmi[i+1]); } ll res2 = INF; set s1, s2; if(num != 0 && num != N-1){ rep(i, num) s1.insert(a[i]); Rep(i, num+1, N) s2.insert(a[i]); res2 = *s1.begin() + a[num] + *s2.begin(); } ll ans = min(res1, res2); if(ans == INF) cout << -1 << endl; else cout << ans << endl; } signed main() { ios::sync_with_stdio(false); cin.tie(0); //cout << fixed << setprecision(10); //init_f(); //init(); //int t; cin >> t; rep(i, t)solve(); solve(); // stop return 0; }