#include <bits/stdc++.h>
#define MAX 500005
#define MOD (ll)(1e9+7)
#define INF (ll)(1e18)
#define inf (1987654321)
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;
int n, m, q;
int a[100005], b[100005];
ll dp[2005][2005];
int main()
{
ios::sync_with_stdio(false);
cin.tie(NULL);
cin >> n >> m;
for(int i = 1; i <= n; ++i) cin >> a[i];
for(int i = 1; i <= m; ++i) cin >> b[i];
vector<int> row, col;
for(int i = 1, p = inf; i <= n; ++i) if(p > a[i]) row.push_back(i), p = a[i];
for(int i = 1, p = inf; i <= m; ++i) if(p > b[i]) col.push_back(i), p = b[i];
int rmx = row.back(), cmx = col.back();
for(int i = n, p = inf; i >= rmx; --i) if(p > a[i]) row.push_back(i), p = a[i];
for(int i = m, p = inf; i >= cmx; --i) if(p > b[i]) col.push_back(i), p = b[i];
sort(row.begin(), row.end()); row.erase(unique(row.begin(), row.end()), row.end());
sort(col.begin(), col.end()); col.erase(unique(col.begin(), col.end()), col.end());
for(int i = 0; i < (int)col.size(); ++i) dp[0][i] = (ll)a[row[0]] * (col[i] - 1);
for(int i = 1; i < (int)row.size(); ++i) {
for(int j = 0; j < (int)col.size(); ++j) {
if(j == 0) dp[i][0] = (ll)b[col[0]] * (row[i] - 1);
else {
dp[i][j] = INF;
dp[i][j] = min(dp[i][j], dp[i - 1][j] + (ll)b[col[j]] * (row[i] - row[i - 1]));
dp[i][j] = min(dp[i][j], dp[i][j - 1] + (ll)a[row[i]] * (col[j] - col[j - 1]));
}
}
}
cout << dp[row.size() - 1][col.size() - 1];
return 0;
}
