1 #include<cstdio>
 2 #include<algorithm>
 3 using namespace std;
 4 int n;
 5 int last,now;
 6 int cnt=0;
 7 int main(){
 8     scanf("%d",&n);
 9     last=0;
10     for (int i=1;i<=n;i++){
11         scanf("%d",&now);
12         if (now>last) cnt+=now-last;
13         last=now;
14     }
15     printf("%d\n",cnt);
16     return 0;
17 }