/**
 * @author : cyb1010
 * @date   : 2024-10-15 17:51:37
 * @file   : machine.cpp
 */
#include <bits/stdc++.h>
using namespace std;
#define fo(s) freopen(s ".in", "r", stdin), freopen(s ".out", "w", stdout)
#define fi first
#define se second
#define ALL(v) (v).begin(), (v).end()
#define SZ(v) int(v.size())
typedef double db;
typedef long double ldb;
typedef long long ll;
typedef unsigned long long ull;
void ckmx(int &x, int y) { x < y && (x = y); }
void ckmn(int &x, int y) { x > y && (x = y); }
const int N = 1010;
int __, _, n, C, c[N][2], f[N][N], fr[N][N], t[N];
string a, b;
vector<int> Ba, Bb[2];
vector<pair<int, int>> ans;
int F(int x) { return (C + 4) * (x / 2) + (x % 2) * (C + 3); }
int main() {
    // fo("machine");
    cin.tie(0)->sync_with_stdio(0);
    cin >> _ >> n >> C >> a >> b;
    for (int i = 1; i <= n; i++) {
        if (a[i - 1] == 'B') Ba.push_back(i);
        if (b[i - 1] == 'B') Bb[i & 1].push_back(i);
        c[i][0] = SZ(Bb[0]), c[i][1] = SZ(Bb[1]);
    }
    memset(f, 0x3f, sizeof(f)), f[0][0] = 0;
    for (int i = 0; i <= c[n][0]; i++)
        for (int j = 0; j <= c[n][1]; j++) {
            if (i < c[n][0]) {
                int x = f[i][j] + F(abs(Ba[i + j] - Bb[0][i]))
                        + max(0, c[Bb[0][i]][1] - j);
                if (x < f[i + 1][j]) f[i + 1][j] = x, fr[i + 1][j] = 0;
            }
            if (j < c[n][1]) {
                int x = f[i][j] + F(abs(Ba[i + j] - Bb[1][j]))
                        + max(0, c[Bb[1][j]][0] - i);
                if (x < f[i][j + 1]) f[i][j + 1] = x, fr[i][j + 1] = 1;
            }
        }
    for (int i = c[n][0], j = c[n][1]; i || j;)
        t[Ba[i + j]] = (!fr[i][j] ? Bb[0][--i] : Bb[1][--j]);
    for (int i = n; i; i--)
        if (t[i] > i) {
            for (int j = i + 2; j <= t[i]; j += 2) ans.emplace_back(j - 2, j);
            if ((t[i] - i) & 1) ans.emplace_back(t[i] - 1, t[i]);
        }
    for (int i = 1; i <= n; i++)
        if (t[i] && t[i] < i) {
            for (int j = i - 2; j >= t[i]; j -= 2) ans.emplace_back(j, j + 2);
            if ((i - t[i]) & 1) ans.emplace_back(t[i], t[i] + 1);
        }
    cout << SZ(ans) << '\n';
    for (auto [l, r] : ans) cout << l << ' ' << r << '\n';
    return 0 ^ __ ^ 0;
}