#include "meetings.h"
#include<bits/stdc++.h>
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx,avx2,bmi,bmi2,popcnt,lzcnt")
using namespace std;
#define ll long long
#define OVL(v,s) for(auto x:v) cout<<x<<s;cout<<endl;
#define all(v) v.begin(),v.end()
#define F first
#define S second
#define pb push_back
void dbg_out() { cout << endl; }
template<typename Head, typename... Tail> void dbg_out(Head H, Tail... T) { cout << ' ' << H; dbg_out(T...); }
#define dbg(...) cout << "(" << #__VA_ARGS__ << "):", dbg_out(__VA_ARGS__);
#define endl "\n"
#define mod 1000000007
const ll INF=1e6;
const ll MAXN=1e5;
const ll LOGN=18;
struct Node1{
ll sum=0;
ll left=0;
ll right=0;
ll mx=0;
};
Node1 merge(Node1 a,Node1 b){
Node1 c;
c.left=max(a.left,a.sum+b.left);
c.right=max(b.right,b.sum+a.right);
c.sum=a.sum+b.sum;
c.mx=max({a.mx,b.mx,a.right+b.left});
return c;
}
struct Node{
Node1 val;
Node* left,*right;
Node() : val({0,0,0,0}),left(nullptr),right(nullptr) {}
};
Node* root;
vector<ll> v;
ll n;
ll arr[MAXN];
void build(Node* node,ll l,ll r){
if(l==r){
node->val={arr[l],arr[l],arr[l],arr[l]};
return;
}
ll mid=(l+r)/2;
node->left=new Node();
node->right=new Node();
build(node->left,l,mid);
build(node->right,mid+1,r);
node->val=merge(node->left->val,node->right->val);
}
Node1 query(Node* node,ll l,ll r,ll ql,ll qr){
if(ql<=l&&r<=qr) return node->val;
Node1 ans;
ll mid=(l+r)/2;
// dbg(l,r);
if(ql<=mid&&qr>mid){
ans=merge(
query(node->left,l,mid,ql,qr),
query(node->right,mid+1,r,ql,qr)
);
return ans;
}
else if(ql<=mid) return query(node->left,l,mid,ql,qr);
else return query(node->right,mid+1,r,ql,qr);
}
vector<long long> minimum_costs(vector<int> H, vector<int> L,vector<int> R) {
n=H.size();
for(auto x:H){
v.push_back(x);
}
root = new Node();
ll q=L.size();
vector<ll> anss(q,10);
for(ll i=0;i<n;i++){
if(v[i]==2){
arr[i]=-INF;
continue;
}
else arr[i]=1;
}
build(root,0,n-1);
for(ll i=0;i<q;i++){
ll l=L[i];
ll r=R[i];
// dbg(l,r);
ll Y=2*(r-l+1);
ll a=query(root,0,n-1,l,r).mx;
dbg(a);
anss[i]=-max(0LL,a)+Y;
}
// dbg(query(root,0,n-1,2,4).mx);
return anss;
}
#ifdef IOI
#include <cstdio>
#include <cstdlib>
#include <vector>
#include "meetings.h"
namespace {
ll read_int() {
ll x;
if (scanf("%lld", &x) != 1) {
fprintf(stderr, "Error while reading input\n");
exit(1);
}
return x;
}
} // namespace
signed main() {
ll N = read_int();
ll Q = read_int();
std::vector<int> H(N);
for (int i = 0; i < N; ++i) {
H[i] = read_int();
}
std::vector<int> L(Q), R(Q);
for (ll j = 0; j < Q; ++j) {
L[j] = read_int();
R[j] = read_int();
}
std::vector<long long> C = minimum_costs(H, L, R);
for (size_t j = 0; j < C.size(); ++j) {
printf("%lld\n", C[j]);
}
return 0;
}
#endif
// ll lg[MAXN];
// ll st[MAXN][LOGN];
// //sparse table
// void build(){
// for(ll i=0;i<n;i++) st[i][0]=v[i];
// for(ll j=1;j<LOGN;j++){
// for(ll i=0;i+(1<<j)<=n;i++){
// st[i][j]=max(
// st[i][j-1],
// st[i+(1<<(j-1))][j-1]
// );
// }
// }
// lg[1]=0;
// for(ll i=2;i<MAXN;i++){
// lg[i]=lg[i/2]+1;
// }
// }
// ll query(ll l,ll r){
// ll k=r-l+1;
// k=lg[k];
// return max(
// st[l][k],
// st[r-(1<<k)+1][k]
// );
// }
