#include <cstdio>
#include <iostream>
using namespace std;
const int M = 200005;
#define int long long
const int MOD = 1e9+7;
int read()
{
	int x=0,f=1;char c;
	while((c=getchar())<'0' || c>'9') {if(c=='-') f=-1;}
	while(c>='0' && c<='9') {x=(x<<3)+(x<<1)+(c^48);c=getchar();}
	return x*f;
}
int n,m,k,w,ans,c[M],dp[M][2][2],g[M],f[M];char s[M];
void work()
{
	dp[1][0][0]=dp[1][1][1]=1;
	for(int i=2;i<=n;i++)
	{
		dp[i][0][0]=(dp[i-1][0][0]+dp[i-1][0][1])%MOD;
		dp[i][0][1]=dp[i-1][0][0];
		dp[i][1][0]=(dp[i-1][1][0]+dp[i-1][1][1])%MOD;
		dp[i][1][1]=dp[i-1][1][0];
	}
	ans=(dp[n][0][0]+dp[n][0][1]+dp[n][1][0])%MOD;
	printf("%lld\n",ans);
}
signed main()
{
	n=read();m=read();scanf("%s",s+1);
	for(int i=1,j=1;i<=m;i=j)
	{
		j=i;while(j<=m && s[i]==s[j]) j++;
		c[++k]=j-i;
	}
	if(k==1) {work();return 0;}
	if(n&1) {puts("0");return 0;}
	w=c[1]+!(c[1]&1);
	for(int i=3;i<k;i+=2)
		if(c[i]&1) w=min(w,c[i]);
	f[0]=g[0]=1;
	for(int i=2;i<=n;i+=2)
	{
		f[i]=(g[i-2]+(i-w-3>=0?MOD-g[i-w-3]:0))%MOD;
		g[i]=(g[i-2]+f[i])%MOD;
	}
	for(int i=2;i<=min(n,w+1);i+=2)
		ans=(ans+f[n-i]*i)%MOD;
	printf("%lld\n",ans);
}