#include <bits/stdc++.h>
using namespace std;
int pre[11000];
string s1[11000], s2[80];
int main()
{
    int n, m; scanf("%d%d", &n, &m);
    for(int i=1; i < n; i++, j=pre[i])
	{
        while(j > 0 && s1[i+1] != s1[j+1]) j=pre[j];
        if(s1[i+1] == s1[j+1]) pre[i+1] = j+1;
    }
    int H = n - pre[n];
    for(int i=1; i <= m; i++) for(int j=1; j <= H; j++) s2[i] += s1[j][i-1];
    memset(pre, 0, sizeof(pre));
    for(int i=1, j=pre[i]; i < m; i++, j=pre[i])
	{
        while(j > 0 && s2[i+1] != s2[j+1]) j=pre[j];
        if(s2[i+1] == s2[j+1]) pre[i+1] = j+1;
    }
    printf("%lld", 1ll * (m - pre[m]) * H);
    return 0;
}

#include<bits/stdc++.h>
using namespace std;
int pre[11000];
string s1[11000],s2[80];
int main()
{
    int n,m;scanf("%d%d",&n,&m);
    for(int i=1;i<=n;i++) cin>>s1[i];
    memset(pre,0,sizeof(pre));
    for(int i=1,j=pre[i];i<n;i++,j=pre[i])
	{
        while(j>0&&s1[i+1]!=s1[j+1])j=pre[j];
        if(s1[i+1]==s1[j+1])pre[i+1]=j+1;
    }
    int H=n-pre[n];
    for(int i=1;i<=m;i++)for(int j=1;j<=H;j++) s2[i]+=s1[j][i-1];
    memset(pre,0,sizeof(pre));
    for(int i=1,j=pre[i];i<m;i++,j=pre[i])
	{
        while(j>0&&s2[i+1]!=s2[j+1]) j=pre[j];
        if(s2[i+1]==s2[j+1])pre[i+1]=j+1;
    }
    printf("%lld",1ll*(m-pre[m])*H);
    return 0;
}