cf-1395-B

/*    BISMILLAHIR-RAHMANIR-RAHIM
 ____________________________________
|                                    |
|       SHANTO_SUST_SWE-19_029       |
|____________________________________|
*/

#include <bits/stdc++.h>

using namespace std;

#define ll          long long
#define fastio      ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL)
#define pb          push_back
#define Pi          acos(-1.0)
#define r0          return 0
#define endl        "\n"
#define show(x)     cout << x << endl
#define take(x)     cin >> x
#define debug       1

int main()
{
    int n, m, x, y, k;
    char ch;
    cin >> n >> m >> x >> y;

    int i, j;
    cout << x << " " << y << endl;
    for(i = y + 1; i <= m; i++) {
        cout << x << " " << i << endl;
    }
    for(i = y - 1; i > 0; i--) {
        cout << x << " " << i << endl;
    }

    for(i = 1; i < x; i++) {
        if (i % 2) {
            for(j = 1; j <= m; j++) {
                cout << i << " " << j << endl;
            }
            ch = 'R';
        }
        else {
            for(j = m; j > 0; j--) {
                cout << i << " " << j << endl;
            }
            ch = 'L';
        }
    }

    if(ch == 'R') k = 1;
    else k = 0;

    for(i = x + 1; i <= n; i++) {
        if (k % 2 == 0) {
            for(j = 1; j <= m; j++) {
                cout << i << " " << j << endl;
            }
            k++;
        }
        else {
            for(j = m; j > 0; j--) {
                cout << i << " " << j << endl;
            }
            k++;
        }
    }


    r0;
}

//ALHAMDULILLAH