#include <iostream>
#include <algorithm>
#include <vector>
#include <iterator>
using namespace std;
 
int main()
{
	vector<int> stairs;
	copy(istream_iterator<int>(cin), istream_iterator<int>(), back_inserter(stairs));
	int water = 0;
	for (int i = *max_element(stairs.begin(), stairs.end()), S = 0; i >= 0; --i, S = 0)
		for (int j = 0, counter = 0; j < stairs.size(); ++j)
			!S ? S = stairs[j] >= i : (stairs[j] < i ? ++counter : 
				(water += counter, S = counter = 0, j--));
	cout << water << endl;
}

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

Mgo1CjEKMgozCjQKNwo3CjY=

2
5
1
2
3
4
7
7
6