#include <iostream>
using namespace std;
int main(){
unsigned int ilosc;
cin >> ilosc;
long long zysk[ilosc];
for(int i = 0; i < ilosc; i++){
long long j;
cin >> j;
zysk[i] = j;
}
long long posy = 0;
long long nega = 0;
for(int i = 0; i < sizeof(zysk); i++){
if(zysk[i] < 0) nega += zysk[i];
else posy += zysk[i];
}
cout << posy+nega;
}
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