#include <bits/stdc++.h>
#include "secret.h"
const int N = 1e3 + 10;
int n, a[N], prer[10][N], prel[10][N];
//int Secret( int a, int b ) { return a + b; }
void solve( int l = 1, int r = n, int cnt = 1 ) {
if( cnt > 8 || l == r ) return ;
int mid = l + r >> 1;
prer[cnt][mid+1] = a[mid+1];
prel[cnt][mid] = a[mid];
for( int i = mid - 1 ; i >= l ; i-- ) prel[cnt][i] = Secret( prel[cnt][i+1], a[i] );
for( int i = mid + 2 ; i <= r ; i++ ) prer[cnt][i] = Secret( prer[cnt][i-1], a[i] );
solve( l, mid, cnt+1 ), solve( mid+1, r, cnt+1 );
}
void Init( int N, int A[] ) {
n = N;
for( int i = 1 ; i <= n ; i++ ) a[i] = A[i-1];
solve();
}
int cal( int ll, int rr, int l = 1, int r = n, int cnt = 1 ) {
if( rr == ll ) return a[ll];
if( rr == ll + 1 ) return Secret( a[ll], a[rr] );
int mid = l + r >> 1;
if( ll <= mid && mid + 1 <= rr ) return Secret( prel[cnt][ll], prer[cnt][rr] );
else if( rr <= mid ) return cal( ll, rr, l, mid, cnt + 1 );
else return cal( ll, rr, mid + 1, r, cnt + 1 );
}
int Query( int L, int R ) { return cal( L+1, R+1 ); }
/*int main()
{
int n, x[N], q;
scanf("%d",&n);
for( int i = 0 ; i < n ; i++ ) scanf("%d",&x[i]);
Init( n, x );
scanf("%d",&q);
while( q-- ) {
int a, b;
scanf("%d %d",&a,&b);
printf("%d\n",Query( a, b ) );
}
}*/
