#include <stdio.h>
#include <string.h>
#define N 1000
#define MD 1000000007
int pp2[N + 1];
void init() {
int i;
pp2[0] = 1;
for (i = 1; i <= N; i++)
pp2[i] = pp2[i - 1] * 2 % MD;
}
int solve(char *aa, char *cc, int n, int k, int lt) {
static char bb[N + 1];
static int dp[N + 1][2], dq[N + 1][2];
int i, j;
bb[0] = '1';
for (i = 0; i < n - 1; i++)
bb[i + 1] = cc[i] == 'L' ? '0' : '1';
for (j = 0; j <= k; j++)
dp[j][0] = dp[j][1] = 0, dq[j][0] = dq[j][1] = 0;
dp[0][0] = 1, dq[0][0] = 0;
for (i = 0; i < n; i++) {
int a = aa[i] - '0', b = bb[i] - '0';
for (j = k; j >= 0; j--) {
int x0 = dp[j][0], y0 = dq[j][0], x1 = dp[j][1], y1 = dq[j][1], b_;
dp[j][0] = dp[j][1] = dq[j][0] = dq[j][1] = 0;
b_ = b ^ j % 2;
if (b_ != a) {
dp[j][1] = (dp[j][1] + x1) % MD;
dq[j][1] = (dq[j][1] + y1 + (long long) pp2[n - 1 - i] * x1 % MD * b_) % MD;
if (b_ < a) {
dp[j][1] = (dp[j][1] + x0) % MD;
dq[j][1] = (dq[j][1] + y0 + (long long) pp2[n - 1 - i] * x0 % MD * b_) % MD;
}
} else {
dp[j][0] = (dp[j][0] + x0) % MD;
dq[j][0] = (dq[j][0] + y0 + (long long) pp2[n - 1 - i] * x0 % MD * b_) % MD;
dp[j][1] = (dp[j][1] + x1) % MD;
dq[j][1] = (dq[j][1] + y1 + (long long) pp2[n - 1 - i] * x1 % MD * b_) % MD;
}
if (j < k) {
b_ = b ^ (j + 1) % 2;
if (b_ != a) {
dp[j + 1][1] = (dp[j + 1][1] + x1) % MD;
dq[j + 1][1] = (dq[j + 1][1] + y1 + (long long) pp2[n - 1 - i] * x1 % MD * b_) % MD;
if (b_ < a) {
dp[j + 1][1] = (dp[j + 1][1] + x0) % MD;
dq[j + 1][1] = (dq[j + 1][1] + y0 + (long long) pp2[n - 1 - i] * x0 % MD * b_) % MD;
}
} else {
dp[j + 1][0] = (dp[j + 1][0] + x0) % MD;
dq[j + 1][0] = (dq[j + 1][0] + y0 + (long long) pp2[n - 1 - i] * x0 % MD * b_) % MD;
dp[j + 1][1] = (dp[j + 1][1] + x1) % MD;
dq[j + 1][1] = (dq[j + 1][1] + y1 + (long long) pp2[n - 1 - i] * x1 % MD * b_) % MD;
}
}
}
}
return (dq[k][1] + (lt ? 0 : dq[k][0])) % MD;
}
int main() {
static char cc[N + 1], aa[N + 1], bb[N + 1];
int n, k, i, ans;
init();
scanf("%d%d%s%s%s", &n, &k, cc, aa, bb);
ans = (solve(bb, cc, n, k, 0) - solve(aa, cc, n, k, 1)) % MD;
for (i = 0; i < n - 1; i++)
cc[i] = cc[i] == 'L' ? 'R' : 'L';
ans = ((long long) ans + solve(bb, cc, n, k, 0) - solve(aa, cc, n, k, 1)) % MD;
if (ans < 0)
ans += MD;
printf("%d\n", ans);
return 0;
}
