#include<iostream>
#include <bits/stdc++.h>

#define ll long long
#define IO ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
using namespace std;
const int N = 500 + 5, inf = 2e9;

string s[N];
int go[N][20009];
int n, m;

void preprocess() {

    for (int i = 0; i + 1 < n; i++) {
        go[i][m] = m;
        for (int j = m - 1; j >= 0; j--) {
            if (s[i][j] != s[i + 1][j]) {
                go[i][j] = j;
            } else {
                go[i][j] = go[i][j + 1];
            }
        }
    }
}

int solve(int idx) {
    int r = 0;
    for (int i = 0; i + 1 < n; i++) {
        int nxt = go[i][idx];
        if (nxt == m || s[i][nxt] > s[i + 1][nxt]) return 1e9;
        r = max(r, nxt);
    }
    return r;
}

void doWork() {
    cin >> n >> m;
    for (int i = 0; i < n; i++) {
        cin >> s[i];
    }
    preprocess();

    int l = 0, r = m - 1;
    for (int i = 0; i < m; i++) {
        int ans = solve(i);
        if (ans - i < r - l) {
            l = i;
            r = ans;
        }
    }
    cout << l + 1 << " " << r + 1;
}

int main() {
    IO
    int t = 1;
    //cin >> t;
    for (int i = 1; i <= t; i++) {
        //  cout << "Case #" << i << ": ";
        doWork();
    }
}