ll@n,@q,@a[n],x[n+1],c[n+1];
x[0]=0,c[0]=0;
rep(i,n){
	x[i+1] = x[i] + a[i];
	c[i+1] = c[i] + a[i] * (a[i] + 1) / 2;
}
rep(q){
	ll@s;
	if(c[n]<s){
		wt(-1);
		continue;
	}
	ll l = lower_bound(c, c + n + 1, s) - c;
	wt(x[l-1]+int(sqrt(2.*(s-c[l-1]))+.5));
}