2185

/*
KMP算法

错了好几次，理解出错，其实是要求出个最基本的小矩阵，能够产生原来的矩阵
这个基本矩阵不一定比原来的矩阵小


*/

// include file
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <cctype>
#include <ctime>

#include <iostream>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <bitset>
#include <strstream>

#include <algorithm>
#include <string>
#include <vector>
#include <queue>
#include <set>
#include <list>
#include <functional>

using namespace std;

// typedef
typedef long long LL;
typedef unsigned long long ULL;

// 
#define read freopen("in.txt","r",stdin)
#define write freopen("out.txt","w",stdout)
#define FORi(a,b,c) for(int i=(a);i<(b);i+=c)
#define FORj(a,b,c) for(int j=(a);j<(b);j+=c)
#define FORk(a,b,c) for(int k=(a);k<(b);k+=c)
#define FORp(a,b,c) for(int p=(a);p<(b);p+=c)

#define FF(i,a)    for(int i=0;i<(a);i+++)
#define FFD(i,a)   for(int i=(a)-1;i>=0;i--)
#define Z(a) (a<<1)
#define Y(a) (a>>1)

const double eps = 1e-6;
const double INFf = 1e10;
const int INFi = 1000000000;
const double Pi = acos(-1.0);

template<class T> inline T sqr(T a){return a*a;}
template<class T> inline T TMAX(T x,T y)
{
	if(x>y) return x;
	return y;
}
template<class T> inline T TMIN(T x,T y)
{
	if(x<y) return x;
	return y;
}
template<class T> inline void SWAP(T &x,T &y)
{
	T t = x;
	x = y;
	y = t;
}
template<class T> inline T MMAX(T x,T y,T z)
{
	return TMAX(TMAX(x,y),z);
}


// code begin
#define MAXR 10010
#define MAXC 80
int R,C;
char rec[MAXR][MAXC];
char P[MAXR];
int next[MAXR];
int Ps;

LL gcd(LL m,LL n)
{
	if(m%n==0)
		return n;
	LL r = m%n;
	return gcd(n,r);
}

void CalNext()
{
	next[0] = 0;
	next[1] = 0;
	int j;
	FORi(2,Ps+1,1)
	{
		j = next[i-1];
		while(true)
		{
			if(P[i-1]==P[j])
			{
				next[i] = j+1;
				break;
			}
			if( j==0 )
			{
				next[i] = 0;
				break;
			}
			j = next[j];
		}
	}
}

int main()
{
	read;
	write;
	LL row,col,cur;
	while(scanf("%d %d",&R,&C)!=-1)
	{
		FORi(0,R,1)
		{
			scanf("%s",rec[i]);
		}
	
		// 对行做一次CalNext
		Ps = C;
		row = 1;
		FORi(0,R,1)
		{
			strcpy(P,rec[i]);
			CalNext();

			cur = Ps-next[Ps];

			row = (row*cur)/gcd(row,cur);
		}


		// 对行进行一次CalNext
		Ps = R;
		col = 1;
		FORi(0,C,1)
		{
			for(int j=0;j<Ps;j++)
				P[j] = rec[j][i];
			P[Ps] = 0;

			CalNext();

			cur = Ps-next[Ps];

			col = (col*cur)/gcd(col,cur);
		}

		if(row>=C) row = C;
		if(col>=R) col = R;

		printf("%lld\n",row*col);
	}

	return 0;
}