积木大赛
#include<iostream>
using namespace std;
const int N=100010;
int h[N],b[N];
int n;
int main(){
cin>>n;
for(int i=1;i<=n;i++)cin>>h[i];
//求h[]数组的差分数组b[]
for(int i=1;i<=n;i++){
b[i]+=h[i];
b[i+1]-=h[i];
}
int res=0;
for(int i=1;i<=n;i++)
if(b[i]>0)res+=b[i];
cout<<res<<endl;
return 0;
}