#include <iostream>
#include <cstdio>
using namespace std;

int main()
{
    #ifndef ONLINE_JUDGE
        freopen("date.in","r",stdin);
        freopen("date.out","w",stdout);
    #endif
    int  x = 0, y, n, sol = 0,energy = 0;
    cin >> n;
    for(int i = 1;i <= n; ++i)
    {
        cin >> y;
        energy += x-y;
        if(energy < 0){
            sol += -energy;
            energy = 0;
        }
        x = y;
    }
    cout<<sol<<"\n";
    return 0;
}