#include <bits/stdc++.h>
using namespace std;
long long int expo_fast(long long int a, long long int b) {
  a = a;
  long long int result = 1;
  while (b) {
    if (b & 1) result = (result * a);
    b >>= 1;
    a = (a * a);
  }
  return (result);
}
void take_in(vector<long long int>* arr) {
  for (int i = 0; i < arr->size(); i++) cin >> (*(arr))[i];
}
void disp_arr(vector<long long int>* arr) {
  for (int i = 0; i < arr->size(); i++) cout << (*(arr))[i] << " ";
}
long long int gcd(long long int a, long long int b) {
  if (b == 0) return a;
  return gcd(b, a % b);
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  int n, m;
  cin >> n >> m;
  vector<pair<long long int, int>> b(n), g(m);
  for (int i = 0; i < n; i++) {
    long long int x;
    cin >> x;
    b[i] = make_pair(x, i);
  }
  for (int i = 0; i < m; i++) {
    long long int x;
    cin >> x;
    g[i] = make_pair(x, i);
  }
  sort(b.begin(), b.end());
  sort(g.begin(), g.end());
  bool cond = (g[0].first >= b[n - 1].first);
  if (n == 1) {
    bool f = false;
    long long int sum = 0;
    for (int i = 0; i < m && cond; i++) {
      sum += g[i].first;
      if (g[i].first == b[0].first) {
        f = true;
      }
    }
    if (f && cond) {
      cout << sum;
    } else
      cout << -1;
  } else if (m == 1) {
    bool f = false;
    long long int sum = 0;
    for (int i = 0; i < n; i++) {
      sum += b[i].first;
      if (b[i].first == g[0].first) {
        f = true;
      }
    }
    if (f && cond)
      cout << sum;
    else
      cout << -1;
  } else {
    int min_index = 0;
    long long int sum = 0, ans = 0;
    for (int i = 0; i < n; i++) {
      sum += b[i].first;
    }
    for (int i = 0; i < m; i++) {
      if (i == min_index && g[i].first != b[n - 1].first) {
        ans += (sum - b[n - 2].first + g[i].first);
      } else {
        ans += (sum - b[n - 1].first + g[i].first);
      }
    }
    if (cond)
      cout << ans;
    else
      cout << -1;
  }
}
