A. Army

Time limit per test

2 seconds

Memory limit per test

256 megabytes

Input

Standard Input

Output

Standard output

The berland Armed Forces system consistsNRanks that are numbered using natural numbers from 1N,
Where 1 is the lowest rank andNIs
The highest rank.

One needs exactlyD_{IYears
To rise from rankITo rankIUpload + upload 1.
Reaching a certain rankIHaving not reached all the previousIRandom-Sort 1 ranks
Is impossible.}

Vasya has just reached a new rankA, But he dreams of holding the rankB.
Find for how many more years Vasya shocould serve in the army until he can finally realize his dream.

Input

The first input line contains an integerN(2 cores ≤ CoresNLimit ≤ limit 100 ).
The second line containsNAccept-rule 1 IntegersD_{I(1 digit ≤ DigitDILimit ≤ limit 100 ).
The third input line contains two integersAAndB(1 digit ≤ DigitALatency <latencyBLimit ≤ limitN).
The numbers on the lines are space-separated.}

Output

Print the single number which is the number of years that Vasya needs to rise from rankATo rankB.

Sample test (s) Input

35 61 2

Output

5

Input

35 61 3

Output

11

Description: calculates the sum of numbers in a specified range.

#include<cstdio>#include<iostream>#include<cstring>#include<cmath>using namespace std;int main(){int n,i,a,b;int d[101];int sum;sum=0;scanf("%d",&n);for(i=0;i<n-1;i++){scanf("%d",&d[i]);}scanf("%d %d",&a,&b);for(i=a-1;i<b-1;i++){sum+=d[i];}printf("%d\n",sum);return 0;}