=

#include<bits/stdc++.h>
using namespace std;
int n,m,i,j;
int a[505][105],minn=INT_MAX,f[105][105];
int main()
{
  cin>>n>>m;
  for(i=1;i<=n;++i)
  for(j=1;j<=m;++j)
  cin>>a[i][j];
  for(i=1;i<=m;++i)
  f[1][i]=a[1][i];
  for(i=2;i<=n;++i)
  {
    for(j=1;j<=m;++j)
	{
      if(j==1)f[i][j]=a[i][j]+f[i-1][j];
      else f[i][j]=a[i][j]+min(f[i-1][j],f[i][j-1]); 
	}
    
    for(j=m-1;j>=1;--j)
    f[i][j]=min(f[i][j],f[i][j+1]+a[i][j]);
  }
  for(j=1;j<=m;++j)
  if(f[n][j]<minn)
  minn=f[n][j];
  cout<<minn;
  return 0;
}