#include <bits/stdc++.h>
#define int long long
using namespace std;
const int INF = 1e18;
signed main(void) {
ios_base::sync_with_stdio(false);
cin.tie(0);
int nbLig, nbCol;
cin >> nbLig >> nbCol;
vector<int> deltaCol(nbLig), deltaLig(nbCol);
for (int &x : deltaCol)
cin >> x;
for (int &x : deltaLig)
cin >> x;
vector<vector<int>> dp(nbLig, vector<int>(nbCol, INF));
for (int lig = nbLig - 1; lig >= 0; --lig) {
for (int col = nbCol - 1; col >= 0; --col) {
if (lig == nbLig - 1) {
dp[lig][col] = (nbCol - 1 - col) * deltaCol[lig];
} else {
dp[lig][col] = deltaLig[col] + dp[lig + 1][col];
if (col < nbCol - 1)
dp[lig][col] = min(dp[lig][col], deltaCol[lig] + dp[lig][col + 1]);
}
}
}
cout << dp[0][0] << endl;
}
