#include <bits/stdc++.h>
using namespace std;
const int64_t M = 1e5 + 5;
int64_t n, m, ans, b[M], g[M];
int32_t main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cin >> n >> m;
  for (int64_t i = 0; i < n; i++) {
    cin >> b[i];
    ans += (m * b[i]);
  }
  for (int64_t i = 0; i < m; i++) cin >> g[i];
  sort(b, b + n);
  sort(g, g + m);
  int64_t f = 0;
  for (int64_t i = 0; i < m; i++) {
    auto idx = upper_bound(b, b + n, g[i]) - b;
    if (idx < n) return cout << -1, 0;
    idx--;
    if (b[idx] == g[i]) {
      f = 1;
      continue;
    }
    ans += g[i];
    if (i != m - 1 || f)
      ans -= b[n - 1];
    else
      ans -= b[n - 2];
  }
  cout << ans;
  return 0;
}
