#include <bits/stdc++.h>
using namespace std;
#include <atcoder/all>
using namespace atcoder;
using ll = long long;
using ull = unsigned long long;
using mint = modint998244353;
ll MOD=998244353;
#define all(x) x.begin(), x.end()
#define rep(i, n) for(ll i = 0; (i) < (n); (i)++)
template<class T>
auto comp_idx(const T* ptr){
  return [ptr](auto l_idx, auto r_idx){
    return ptr[l_idx] < ptr[r_idx];
  };
}
template<class T>
vector<ll> IndexSort(T vec){
    vector<ll> ind(vec.size());
    iota(all(ind), 0);
    sort(all(ind), comp_idx(vec.data()));
    return ind;
}
void yn(bool flag){
  string ans = (flag) ? "Yes" : "No";
  cout<<ans<<endl;
}

int main(){
  ll n, x; cin>>n>>x;
  ll ans=0;
  rep(i, n) {
    ll b; cin>>b;
    ans+=b;
  }
  cout<<ans-x<<endl;
}