#include "bits/stdc++.h" using namespace std; int x[1000000]; int main(){ int n,ans=0; cin>>n; for(int i=1;i<=n;i++){ cin>>x[i];} for(int i=1;i<n;i++){ if(x[i+1]>x[i])ans+=(x[i+1]-x[i]);} cout<<ans; }