#include<bits/stdc++.h>
using namespace std;
int main(){
	int n,x,h=0;
	cin>>x>>n;
	int a[n];
	for(int i=0;i<=n-1;i++){
		cin>>a[i];
		h=h+a[i]*x;
	}
	cout<<h;
}
/**************************************************************
	Problem: 2087
	User: wangyiyang
	Language: C++
	Result: Accepted
	Time:47 ms
	Memory:2072 kb
****************************************************************/