tj

#include<bits/stdc++.h>
using namespace std;

int main()
{
    int a,b;
    cin>>a>>b;
    int c[a];
    cin>>c[0];
    for(int i = 1;i<a;i++)
        {    
            int ci;
            cin>>ci;
            c[i]=ci+c[i-1];
        }
    for(int i = 0;i<b;i++)
        {
            int x,y;
            cin>>x>>y;
            if(x==1)
                cout<<c[y-1];
            else
                cout<<c[y-1]-c[x-2];
            cout<<endl;
        }
}