#include <bits/stdc++.h>
using namespace std;
int dp[1001][1001],a[1001][1001];
int n,m;
int main(){
	scanf("%d",&n,&m);
	memset(dp,2147483647,sizeof(dp)); 
	for (int i=1;i<=n;++i) 
		for (int j=1;j<=m;++j)
			scanf("%d",&a[i][j]);
	for (int i=1;i<=n;++i){   
		for (int j=1;j<=m;++j){
			if(i==1&&j==1){
				dp[1][1]=a[1][1];
            		else{
				dp[i][j]=min(min(dp[i-1][j],dp[i+1][j]),min(dp[i-1][j],dp[i][j-1]))+a[i][j]; 
				
			}
		}
	}
	printf("%d",dp[n][m]); 
	return 0;
}

听取WA声一片