1 #include <bits/stdc++.h>
2 #define _for(i,a,b) for(int i = (a);i < b;i ++)
3 #define _rep(i,a,b) for(int i = (a);i > b;i --)
4 typedef long long ll;
5 using namespace std;
6 inline ll read()
7 {
8 ll ans = 0;
9 char ch = getchar(), last = ' ';
10 while(!isdigit(ch)) last = ch, ch = getchar();
11 while(isdigit(ch)) ans = (ans << 1) + (ans << 3) + ch - '0', ch = getchar();
12 if(last == '-') ans = -ans;
13 return ans;
14 }
15 inline void write(ll x)
16 {
17 if(x < 0) x = -x, putchar('-');
18 if(x >= 10) write(x / 10);
19 putchar(x % 10 + '0');
20 }
21
22 int n;
23 int a,b;
24 int main()
25 {
26 n = read();
27 int rnt = 0;
28 _for(i,0,n)
29 {
30 a = read();
31 if(a>b)
32 rnt += a-b;
33 b = a;
34 }
35 write(rnt);
36
37
38 return 0;
39 }
