#include <bits/stdc++.h>
using namespace std;
#define _ <<" "<<
#define sz(x) ((int) (x).size())
typedef pair<int, int> pii;
typedef long long ll;
const int maxn = 500 + 5;
const int maxl = 2e4 + 5;

int n, m;
char s[maxn][maxl];
int L;
int lcp[maxn][maxl];

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cin >> n >> L;
    for (int i = 1;i <= n; ++i) {
        for (int j = 1;j <= L; ++j) {
            cin >> s[i][j];
        }
    }
    for (int i = 1;i < n; ++i) {
        int r = 0;
        for (int l = 1;l <= L; ++l) {
            r = max(r,l-1);
            while (r+1 <= L && s[i][r+1] == s[i+1][r+1]) r++;
            if (r == L || s[i][r+1] > s[i+1][r+1]) lcp[i][l] = INT_MAX/2;
            else lcp[i][l] = r - l + 1;
        }
    }
    int ans = L;
    pii ansp = {1,L};
    for (int l = 1;l <= L; ++l) {
        int cur = 0; 
        for (int i = 1;i < n; ++i) {
            cur = max(cur, lcp[i][l]+1);
        }
        if (cur < ans) {
            ans = cur;
            ansp = {l, l + cur - 1};
        }
    }
    cout << ansp.first _ ansp.second << '\n';
    return 0;
}