MCub

#include <fstream>
using namespace std;
ifstream f("mcub.in");
ofstream g("mcub.out");
int n,H[100001];
long long sol;

int main()
{
    f>>n;
    for(int i=1;i<=n;++i)
        f>>H[i];
    sol=H[0];
    for(int i=1;i<=n;++i)
        if(H[i]>=H[i-1])
            sol+=H[i]-H[i-1];
    g<<sol;
    return 0;
}