#include <bits/stdc++.h>
using namespace std;
bool cmp(long long int x, long long int y) { return x > y; }
long long int a[200005], b[200005];
int main() {
  long long int i, j, m, n, s, w, k, v, sum, sum1;
  while (~scanf("%lld %lld", &n, &m)) {
    v = 0;
    sum = 0;
    sum1 = 0;
    s = 0;
    for (i = 0; i < n; i++) {
      scanf("%lld", &a[i]);
      sum += a[i];
    }
    for (i = 0; i < m; i++) {
      scanf("%lld", &b[i]);
      sum1 += b[i];
    }
    sort(a, a + n, cmp);
    sort(b, b + m, cmp);
    if (a[0] > b[m - 1]) v = 1;
    if (a[0] < b[m - 1]) {
      s = sum1 - b[m - 1] + a[0];
      s = s + b[m - 1] + (m - 1) * a[1];
      s = s + m * (sum - a[0] - a[1]);
    } else if (a[0] == b[m - 1]) {
      s = sum1 + (sum - a[0]) * m;
    }
    if (v == 1)
      printf("-1\n");
    else
      printf("%lld\n", s);
  }
  return 0;
}
