In a flower bed, there are N flowers, numbered 1,2,......,N. Initially, the heights of all flowers are 0. You are given a sequence h=\\{h_1,h_2,h_3,......\\} as input. You would like to change the height of Flower k to h_k for all k (1 \leq k \leq N), by repeating the following "watering" operation:

* Specify integers l and r. Increase the height of Flower x by 1 for all x such that l \leq x \leq r.



Find the minimum number of watering operations required to satisfy the condition.

Constraints

* 1 \leq N \leq 100
* 0 \leq h_i \leq 100
* All values in input are integers.

Input

Input is given from Standard Input in the following format:


N
h_1 h_2 h_3 ...... h_N


Output

Print the minimum number of watering operations required to satisfy the condition.

Examples

Input

4
1 2 2 1


Output

2


Input

5
3 1 2 3 1


Output

5


Input

8
4 23 75 0 23 96 50 100


Output

221
#include <bits/stdc++.h>
using namespace std;

int main() {
  int n;
  cin >>n;
  vector<int>a(n);
  for(int i=0;i<n;i++){
    cin>>a[i];
  }
  long long kotae=a[0];
  for(int i=1;i<n;i++){
    if(a[i]-a[i-1]>0)kotae+=a[i]-a[i-1];
  }
  cout<<kotae<<endl;
  return 0;
}
