积木

#include<cstdio>
#include<iostream>

using namespace std;

int h[100001],ans,n;

int main(){
scanf("%d",&n);
for(int i=0;i<n;i++){
scanf("%d",&h[i]);
if(h[i]>h[i-1])ans+=h[i]-h[i-1];
}
printf("%d\n",ans);
}