#include <bits/stdc++.h>
using namespace std;
const long long MOD = 1e9 + 7;
const long long inf = 10000000;
const double pi = acos(-1.0);
inline bool EQ(double a, double b) { return fabs(a - b) < 1e-9; }
inline bool isLeapYear(long long year) {
  return (year % 400 == 0) || (year % 4 == 0 && year % 100 != 0);
}
inline void normal(long long &a) {
  a %= MOD;
  (a < 0) && (a += MOD);
}
inline long long modMul(long long a, long long b) {
  a %= MOD, b %= MOD;
  normal(a), normal(b);
  return (a * b) % MOD;
}
inline long long modAdd(long long a, long long b) {
  a %= MOD, b %= MOD;
  normal(a), normal(b);
  return (a + b) % MOD;
}
inline long long modSub(long long a, long long b) {
  a %= MOD, b %= MOD;
  normal(a), normal(b);
  a -= b;
  normal(a);
  return a;
}
inline long long modPow(long long b, long long p) {
  long long r = 1;
  while (p) {
    if (p & 1) r = modMul(r, b);
    b = modMul(b, b);
    p >>= 1;
  }
  return r;
}
inline long long modInverse(long long a) { return modPow(a, MOD - 2); }
inline long long modDiv(long long a, long long b) {
  return modMul(a, modInverse(b));
}
inline bool checkBit(long long n, int i) { return n & (1LL << i); }
inline long long setBit(long long n, int i) {
  return n | (1LL << i);
  ;
}
inline long long resetBit(long long n, int i) { return n & (~(1LL << i)); }
int dx[] = {0, 0, 1, -1};
int dy[] = {1, -1, 0, 0};
void input(long long n, const long long a[], int co = 0) {
  long long i = 1;
  for (; i <= n; i++) {
    if (co == 0)
      scanf("%lld", &a[i]);
    else
      printf("%lld ", a[i]);
  }
}
void dfs() {}
bool cmp() {}
void solve() {}
const long long N = 1e5 + 10;
long long a[N];
long long sm = 0, n, m;
int main() {
  scanf("%lld %lld", &n, &m);
  for (int i = 0; i < n; i++) {
    scanf("%lld", &a[i]);
    sm += a[i];
  }
  sort(a, a + n);
  long long tot = 0, pr = 0, nxt = 0;
  for (int i = 0; i < n; i++) {
    int j = i + 1;
    while (j < n and a[i] == a[j]) j++;
    long long nw = a[i] - pr;
    if (nw <= j - i) {
      tot += (j - i);
      if (nxt != 0) {
        tot -= min(nxt, j - i - nw);
        nxt -= min(nxt, nw);
      }
    } else {
      tot += nw;
      nxt += nw - j + i;
    }
    pr = a[i];
    i = j - 1;
  }
  printf("%lld\n", sm - tot);
  return 0;
}
