#include <iostream>
using namespace std;
int main() {
    int n;
    int a[100];
    cin >> n;
    int i,j;
    for (i=0; i<n; i++) { cin >> a[i]; a[i] %= 1000000007; }
    for (i=0; i<n-1; i++) for (j=0; j<n-1; j++) { a[j] += a[j+1]; a[j] %= 1000000007; }
    cout << a[0];
    return 0;
}