#include<iostream>

using namespace std;

int main()
{
    int k, n, S =0;
    cin >> k >> n;

    if (k, n >= 1 && k, n <= 100) {
        int  *A = (int*)malloc(n*sizeof(int));
        for (int i = 0; i < n; i++) {
            cin >> A[i];
            if (!(A[i] >= 0 && A[i] <= 100))
                break;
        }
        for (int i = 0; i < n; i++)
            S += A[i] - k;
        cout << S << endl;
    }
        return 0;
}

Edited by author 05.02.2015 20:02