#include<bits/stdc++.h>
using namespace std;
int n,m,a[100005],b[100005],x,y;
int main(){
    scanf("%d%d",&n,&m);
    for(int i=1;i<=n;i++){
        scanf("%d%d",&a[i]);
        b[i]=b[i-1]+a[i];
	}
    while(m--){
        scanf("%d%d",&x,&y);
        printf("%d\n",b[y]-b[x-1]);
    }
	return 0;
}

/**************************************************************
	Problem: 2060
	User: huangkaiwei
	Language: C++
	Result: Time Limit Exceed
****************************************************************/