#include <cstdio> 
#include <set> 

#define X first
#define Y second

using namespace std;

typedef long long ll;
typedef pair<int, int> pii;

const ll OO = 1e18; 
const int N = 1010;

int n, m, A[N], B[N]; 

ll D[N][N];
set<pair<ll, pii>> S; 

int main() {
	scanf("%d%d", &n, &m); 
	for(int i = 1; i <= n; ++i) scanf("%d", A + i); 
	for(int i = 1; i <= m; ++i) scanf("%d", B + i); 

	for(int i = 1; i <= n; ++i)
		for(int j = 1; j <= m; ++j) {
			if(i == 1 && j == 1) D[i][j] = 0;
			else D[i][j] = OO;
			S.insert({D[i][j], {i, j}});
		}

	while(!S.empty()) {
		int x = (*S.begin()).Y.X;
		int y = (*S.begin()).Y.Y; 	
		S.erase(S.begin()); 

		if(x != n && D[x + 1][y] > (ll) D[x][y] + B[y]) {
			S.erase({D[x + 1][y], {x + 1, y}});
			D[x + 1][y] = (ll) D[x][y] + B[y]; 
			S.insert({D[x + 1][y], {x + 1, y}});
		}

		if(y != m && D[x][y + 1] > (ll) D[x][y] + A[x]) {
			S.erase({D[x][y + 1], {x, y + 1}});
			D[x][y + 1] = (ll) D[x][y] + A[x]; 
			S.insert({D[x][y + 1], {x, y + 1}});
		}
	}

	printf("%lld\n", D[n][m]);
	return 0;
}