#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: yangjunwen
	Language: C++
	Result: Accepted
	Time:49 ms
	Memory:2072 kb
****************************************************************/