#pragma GCC optimize("O3")
#pragma GCC optimize ("unroll-loops")
#pragma GCC optimize ("Ofast,no-stack-protector", "omit-frame-pointer", "inline", "-ffast-math")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,sse4.2,fma,popcnt,abm,mmx,avx")

#include<bits/stdc++.h>

#define ll long long
#define pp push_back
#define endl '\n'
#define all(x) x.begin(),x.end()
#define ld long double
#define PI acos(-1)
#define sin(a) sin((a)*PI/180)
#define cos(a) cos((a)*PI/180)
#define ones(x) __builtin_popcountll(x)
//#define int ll

using namespace std;

void Drakon() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
#ifdef Clion
    freopen("input.txt", "r", stdin), freopen("output.txt", "w", stdout);
#endif
}

unsigned long long inf = 1e10;
const double EPS = 1e-6;
const int MOD = 1000000007, N = 2e4 + 5, LOG = 25;

ll gcd(ll x, ll y) {
    return y ? gcd(y, x % y) : x;
}

ll lcm(ll a, ll b) {
    return (a * b) / __gcd(a, b);
}

int mul(int a, int b) {
    ll ret = 1ll * a * b;
    if(ret >= MOD)ret %= MOD;
    return ret;
}

int add(int a, int b) {
    if(a < 0)a += MOD;
    if(b < 0)b += MOD;
    a += b;
    if(a >= MOD)a -= MOD;
    return a;
}

int pw(int x, int y) {
    int ret = 1;
    while (y > 0) {
        if (y % 2 == 0) {
            x = mul(x, x);
            y = y / 2;
        } else {
            ret = mul(ret, x);
            y = y - 1;
        }
    }
    return ret;
}

const int P1 = 31, P2 = 37;

int pw1[N], pw2[N], inv1[N], inv2[N];

void pre() {
    pw1[0] = inv1[0] = pw2[0] = inv2[0] = 1;
    int mulInv1 = pw(P1, MOD - 2);
    int mulInv2 = pw(P2, MOD - 2);
    for (int i = 1; i < N; i++) {
        pw1[i] = mul(pw1[i - 1], P1);
        pw2[i] = mul(pw2[i - 1], P2);
        inv1[i] = mul(inv1[i - 1], mulInv1);
        inv2[i] = mul(inv2[i - 1], mulInv2);
    }
}

struct Hash {
    vector<int> prefixHash;

    Hash() {

    }

    Hash(string &s) {
        prefixHash = vector<int>(s.size(), 0);
        for (int i = 0; i < s.size(); i++) {
            prefixHash[i] = mul(s[i] - 'a' + 1, pw1[i]);
            if (i)
                prefixHash[i] = add(prefixHash[i], prefixHash[i - 1]);
        }
    }

    int getRangeHashVal(int l, int r) {
        return mul(add(prefixHash[r], -(l ? prefixHash[l - 1] : 0)), inv1[l]);

    }
};


void solve() {
    int n, l;
    cin >> n >> l;
    vector<Hash> vec(n);
    vector<string> s(n);
    for (int i = 0; i < n; ++i) {
        cin >> s[i];

    }
    sort(all(s));
    for (int i = 0; i < n; ++i) {
        vec[i] = Hash(s[i]);
    }

    int a = 0, b = l - 1;
    for (int i = 0; i < l; ++i) {

        int mx = i;
        for (int j = 1; j < n; ++j) {
            int st = i, en = l - 1, ind = -1;
            while (st <= en){
                int mid = (st + en) / 2;
                if(vec[j].getRangeHashVal(i, mid) != vec[j - 1].getRangeHashVal(i, mid)){
                    ind = mid;
                    en = mid - 1;
                }
                else{
                    st = mid + 1;
                }
            }
            if(!~ind || s[j][ind] < s[j - 1][ind]){
                mx = 1e9;
                break;
            }
            mx = max(mx, ind);
        }
        if((mx - i + 1) < (b - a + 1)){
            a = i, b = mx;
        }
    }
    cout << a + 1 << ' ' << b + 1;
}

signed main() {
    Drakon();
    pre();
    int t = 1;
    //cin >> t;
    while (t--) {
        solve();
    }
}