链接:​​https://www.nowcoder.com/acm/contest/211/A​

#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstring>
#include<cmath>
#include<vector>
#include<queue>
#include<set>
#define mem(a,x) memset(a,x,sizeof(a))
#define s1(x) scanf("%d",&x)
#define s2(x,y) scanf("%d%d",&x,&y)
#define s3(x,y,z) scanf("%d%d%d",&x,&y,&z)
#define s4(x,y,z,k) scanf("%d%d%d%d",&x,&y,&z,&k)
#define ls 2*rt
#define rs 2*rt+1
#define lson ls,L,mid
#define rson rs,mid+1,R
#define ll long long
using namespace std;
typedef pair<int,int> pii;
//inline ll ask(int x){ll res=0;while(x)res+=c[x],x-=x&(-x);return res;}
//inline void add(int x,int d){while(x<=n)c[x]+=d,x+=x&(-x);}
//int gcd(int a, int b) { return b == 0 ? a : gcd(b, a%b);}
const ll inf = 0x3f3f3f3f;
const int mx = 0;

void print(__int128 x)
{
if(!x)
{
puts("0");
return ;
}
string ret="";
while(x)
{
ret+=x%10+'0';
x/=10;
}
reverse(ret.begin(),ret.end());
cout<<ret<<endl;
}

int main(){
// freopen("F:\\in.txt","r",stdin);
//int T=10; scanf("%d",&T);
__int128 ans = 0;
int n,x;
s1(n);
for(int i = 1; i<= n ;i++){
s1(x);
if(x >= 0)
ans+=x;
else
ans+=1LL*i*x;
}
if(ans<0){
ans=-ans;
printf("-");
}
print(ans);

return 0;
}