#include <bits/stdc++.h>

#define int long long

using namespace std;

signed main() {
    int t;
    cin >> t;
    while(t--){
        int n;
        cin >> n;
        vector<int> v(n);
        for(int i = 0; i < n; ++i) cin >> v[i];
        int ans = 1e9;
        for(int i = 1; i < n; ++i){
            int temp = max(v[i], v[i - 1]);
            ans = min(ans, temp);
        }
        cout << ans - 1 << '\n';
    }
}