#include<bits/stdc++.h> using namespace std; int a[1005]; int n; int nb() { int ans = 0; for(int i = 1;i <= n;i++) { if(a[i] < a[i + 1]) ans += (a[i + 1] - a[i]); } return ans; } int main() { cin >> n; for(int i = 1;i <= n;i++) cin >> a[i]; cout << nb(); return 0; }