#include <bits/stdc++.h>
using namespace std;
using LL=long long;
using ULL=unsigned long long;
#define rep(i,n) for(int i=0; i<(n); i++)



int N;
LL X;
LL A[200000];

int main(){
  scanf("%d%lld",&N,&X);
  rep(i,N) scanf("%lld",&A[i]);
  LL v=-X*(N-1);
  rep(i,N) v+=A[i];
  printf("%lld\n",v);
  return 0;
}