#include<bits/stdc++.h>
using namespace std;
int main(){
    int n,q,x,a[1000006];
    cin >> n >> q;
    for(int i = 1;i < n;i++){
        cin >> a[i];
    }
    
    for(int w = 0;w < q;w++){
        int x,y;
        cin >> x >> y;
        x = a[x];
        y = a[y];
        int maxn = -1;
        for(int i = 1;i <= n;i++){
            if(a[i] >= maxn && a[i] != x && a[i] != y) maxn = a[i];
        }
        cout << maxn << endl;
    }
    
}
```壶关