#include<iostream>
using namespace std;
using ll = long long;
#define forn(i, n) for(int i=0; i<(int)n; ++i)
#define forsn(i, s, n) for(int i=s; i<(int)n; ++i)
const int MAXN=1010, MOD=1000000007;
int n, k, pot[MAXN], comb[MAXN][MAXN], dp[MAXN][MAXN][2];
string dirs, le, ri;
void pre(string& num){
int pos=num.size()-1;
while(num[pos]=='0') num[pos--]='1';
num[pos]='0';
}
void nxt(string& num){
int pos=num.size()-1;
while(num[pos]=='1') num[pos--]='0';
num[pos]='1';
}
int calc(string num){
int ret=0;
forn(dir, 2){
int xtra=0, sum=0;
bool cur=dir;
forsn(i, 1, num.size()){
bool differs=cur^(num[i]=='0')^(dirs[i-1]=='L');
xtra+=(int)differs;
cur^=differs;
}
forn(i, num.size()) if(num[i]=='1') sum=(sum + pot[n-1-i])%MOD;
if(xtra<=k) ret=(ret+dp[n-num.size()][k+1-xtra][cur]+((ll)comb[n-num.size()][k+1-xtra])*sum)%MOD;
}
return ret;
}
int query(string l, string r){
int ret=0;
for(; l<=r; l.pop_back(), r.pop_back()){
if(l.back()=='1') ret+=calc(l), nxt(l);
if(r.back()=='0') ret+=calc(r), pre(r);
}
return ret;
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cin >> n >> k >> dirs >> le >> ri;
pot[0]=1;
forn(i, n) pot[i+1]=(pot[i]<<1)%MOD;
forn(i, n+1) comb[i][1]=comb[i][i+1]=1;
forsn(i, 2, n+1) forsn(j, 1, n) comb[i][j+1]=(comb[i-1][j+1]+comb[i-1][j])%MOD;
forsn(i, 1, n) forsn(j, 1, i+2) forn(d, 2){
dp[i][j][d]=(dp[i-1][j][d] + dp[i-1][j-1][d^1] + comb[i-1][j-(d^(dirs[n-i-1]=='L'))]*((ll)pot[i-1]))%MOD;
}
cout << query(le, ri) << "\n";
}
