#include <fstream>
#include <iostream>
#define N 105
using namespace std;
ifstream fin(".in");
ofstream fout(".out");
///777
int a[N][N], n, m ;///declarearea unei matrice
int main()
{
    int i,j, i1;

    ///citirea
    cin>>n>>m; /// n-nr de linii , m- nr de coloane
    for(i=1;i<=n;i++)
        for(j=1;j<=m;j++)
          cin>>a[i][j];
    int cnt=0;///nr de coloane cu valori distincte
    /// prelucram coloanele
    for(j=1;j<=m;++j)
    {
        ///coloana j;
        bool ok=1; ///pp ca elem sunt distincte 2 cate 2
        for(i=1;i<n && ok;++i)
            for(i1=i+1; i1<=n && ok;++i1)
              if(a[i][j]==a[i1][j]) ok=0;

        if(ok==1)cnt++;
    }

    cout<<cnt;
    return 0;
}