C++ :

#include<iostream>
#include<algorithm>
using namespace std;
int n,s,a[100008];
int main()
{
	cin>>n;
	for (int i=1;i<=n;i++){
		cin>>a[i];
		if (i!=1&&a[i]>a[i-1]) s+=a[i]-a[i-1];
	}
	cout<<s<<endl;
	return 0;
}