/// Msaa el 5ra
#pragma GCC optimize("O3")
#pragma GCC optimize ("unroll-loops")
#pragma GCC target("avx,avx2,fma")

#include "bits/stdc++.h"

using namespace std;

#define pb push_back
#define F first
#define S second
#define f(i, a, b)  for(int i = a; i < b; i++)
#define all(a)  a.begin(),a.end()
#define rall(a) a.rbegin(),a.rend()
#define sz(x) (int)(x).size()
#define mp(x, y) make_pair(x,y)
#define popCnt(x) (__builtin_popcountll(x))
#define int ll

using ll = long long;
using ii = pair<int, int>;
using ull = unsigned long long;

const int N = 5e5 + 5, LG = 18, MOD = 1e9 + 7;
const long double PI = acos(-1);
const long double EPS = 1e-7;


void doWork() {

    int n, l;
    cin >> n >> l;
    vector<string> vs(n);
    f(i, 0, n) cin >> vs[i];
    vector<int> val(n, INT_MAX);
    array<int, 3> ans({l, 1, l});
    for (int i = l - 1; i >= 0; --i) {
        int r = 0;
        f(j, 1, n) {
            if (vs[j][i] > vs[j - 1][i])val[j] = i;
            if (vs[j][i] < vs[j - 1][i])val[j] = INT_MAX;
            r = max(r, val[j]);
        }
        if ((r - i + 1) <= ans[0]) {
            ans = {r - i + 1, i + 1, r + 1};
        }
    }
    cout << ans[1] << ' ' << ans[2] << '\n';
}

int32_t main() {
#ifdef ONLINE_JUDGE
    ios_base::sync_with_stdio(0);
    cin.tie(0);
#endif // ONLINE_JUDGE

    int t = 1;
//    cin >> t;
    while (t--) {
        doWork();
    }
}