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