104B - Testing Pants for Sadness - CodeForces Solution

#include <iostream>
#include<algorithm>
#define int long long
using namespace std;
int n,ans,a[105];
signed main() {
	ios::sync_with_stdio(false);
	cin.tie(NULL),cout.tie(NULL);
	cin>>n;
	for(int i=1;i<=n;i++)
		cin>>a[i];
	for(int i=1;i<=n;i++)
		ans+=a[i]+(a[i]-1)*(i-1);
	cout<<ans<<'\n';
	return 0;}