import java.io.BufferedReader;
import java.io.InputStreamReader;

class Main
{
	public static void main (String[] args) throws Exception
	{
		BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));
		String[] params1 = bufferedReader.readLine().split(" ");
		int n = Integer.parseInt(params1[0]);
		int m = Integer.parseInt(params1[1]);
		int[][] A = new int[n][m];
		for (int i=0; i<n; i++)	{
	        String[] params2 = bufferedReader.readLine().split(" ");
			for (int j=0; j<m; j++)	{
				A[i][j] = Integer.parseInt(params2[j]);
			}
		}
		for (int i=1; i<n; i++)	{
			A[i][0]+=A[i-1][0];
		}
		for (int i=1; i<m; i++)	{
			A[0][i]+=A[0][i-1];
		}
		for (int i=1; i<n; i++)	{
			for (int j=1; j<m; j++) {
				A[i][j]+=Math.min(A[i-1][j],A[i][j-1]);
			}
		}
		System.out.println(A[n-1][m-1]);
	}
}