#include <algorithm>
#include <array>
#include <cmath>
#include <cstdio>
#include <deque>
#include <iomanip>
#include <iostream>
#include <numeric>
#include <optional>
#include <queue>
#include <set>
#include <stack>
#include <unordered_map>
#include <unordered_set>
#include <vector>

using namespace std;

int main() {
    int32_t n, x;
    cin >> n >> x;
    vector<int32_t> ss(n);
    for (auto &&s : ss) {
        cin >> s;
    }
    auto sum = accumulate(ss.begin(), ss.end(), int64_t(0));
    cout << sum - int64_t(x) * (n - 1) << endl;
    return 0;
}