#include<iostream>#include<cstdio>#include<string>#include<cstring>#include<algorithm>using namespace std;const int maxn = 2050;int n,m,ans;char s[maxn][maxn];bool ok;bool vis[maxn];int main(){    freopen("evensgn.in","r",stdin);    freopen("evensgn.out","w",stdout);    cin>>n>>m;    for(int i = 1;i <= n;i++){            scanf("%s",s[i]+1);    }    memset(vis,true,sizeof(vis));    for(int i = 1;i <= m;i++){        ok = true;        for(int j = 2;j <= n;j++){            if(vis[j]&& s[j][i] < s[j-1][i]){                ans++;                ok = false;                break;            }        }        if(ok){            for(int j = 2;j <= n;j++){                if(s[j][i] != s[j-1][i]) vis[j] = false;            }        }    }    cout<<ans;    return 0;}#include<cstdio>#include<iostream>#include<algorithm>#include<cstring>#include<cmath>#include<vector>#include<queue>#include<map>#include<set>#include<stack>#include<cstdlib>#include<string>#include<bitset>#define INF 100000000#define fi first#define se secondusing namespace std;typedef long long LL;typedef pair<int,int> pii;char s[1005][1005];int rk[1005],trk[1005];int main(){    int n,m,i,j,ans=0,flag;    freopen("evensgn.in","r",stdin);    freopen("evensgn.out","w",stdout);    cin>>n>>m;    for(i=1;i<=n;i++)        scanf("%s",s[i]+1);    for(j=1;j<=m;j++)    {        flag=0;        trk[1]=0;        for(i=1;i<n;i++)        {            if(rk[i]<rk[i+1])            {                trk[i+1]=trk[i]+1;                continue;            }            else            {                if(s[i][j]>s[i+1][j])                {                    ans++;                    //printf("j=%d i=%d\n",j,i);                    flag=1;                    break;                }                else if(s[i][j]<s[i+1][j])                    trk[i+1]=trk[i]+1;                else trk[i+1]=trk[i];            }        }        if(!flag)            for(i=1;i<=n;i++)                rk[i]=trk[i];    }    cout<<ans<<endl;    return 0;}// davidlee1999WTK 2014/// srO myk Orz//ios::sync_with_stdio(false);