#include <bits/stdc++.h>
using namespace std;
long long n, k, ans, mod=1000000007;
string upute, l, r, rj1, rj2;
int main (){
ios::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
cin >> n >> k;
cin >> upute;
cin >> l;
cin >> r;
rj1="1", rj2="1";
for (int i=0; i<n-1; i++){
if (upute[i]=='L') {rj1+='0'; rj2+='1';}
else {rj1+='1'; rj2+='0';}
}
if (l<=rj1 and rj1<=r){
long long sol=0;
for (int i=0; i<n; i++){
sol*=2;
sol+=rj1[i]-'0';
sol%=mod;
} ans+=sol;
}
if (l<=rj2 and rj2<=r){
long long sol=0;
for (int i=0; i<n; i++){
sol*=2;
sol+=rj2[i]-'0';
sol%=mod;
} ans+=sol;
}
cout << ans;
return 0;
}
