#include <bits/stdc++.h>
using namespace std;
using lli = long long;
using lld = long double;
const int maxN = 2 * 1e5 + 1;
const long long mod = 998244353;
void FastInput() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
}
void InputFile() {
  freopen("a.INP", "r", stdin);
  freopen("a.OUT", "w", stdout);
}
int main() {
  FastInput();
  {
    lli n, m, b[maxN], g[maxN], sumb(0), sumg(0);
    cin >> n >> m;
    for (int i = 1; i <= n; i++) {
      cin >> b[i];
      sumb += b[i];
    }
    for (int i = 1; i <= m; i++) {
      cin >> g[i];
      sumg += g[i];
    }
    sort(b + 1, b + n + 1);
    sort(g + 1, g + m + 1);
    if (b[n] > g[1]) cout << -1 << '\n';
    if (b[n] == g[1]) {
      cout << (sumb - b[n]) * m + sumg << '\n';
    }
    if (b[n] < g[1]) {
      cout << b[n] + b[n - 1] * (m - 1) + (sumb - b[n] - b[n - 1]) * m + sumg
           << '\n';
    }
  }
}
