#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#pragma GCC target("avx2")
using namespace std;

#define int long long
using ll = __int128;
const int num_mods = 2;

const ll MOD1 = 4.7e17+1;
const array<ll, num_mods> mods = { MOD1, MOD1+3, MOD1+5, MOD1+7 };

array<int, num_mods> transform(vector<int> digits) {
    array<int, num_mods> res;
    for(int M = 0; M < num_mods; M++) {
        ll cur = 1, ans = 0;
        for(auto i : digits) {
            ans = (ans + cur * 1ll * i) % mods[M];
            cur = cur*10ll % mods[M];
        }
        res[M] = ans;
    }
    return res;
}

main() {
    ios_base::sync_with_stdio(0);
    cout.tie(0);

    signed n, k;

//    n = 500;
//    k = 19000;
    cin >> n >> k;
    vector<string> s(n);
    vector<vector<int>> nums;
    for(auto &x : s) {
        cin >> x;
//        x = string(20000, '7');

        reverse(x.begin(), x.end());
        vector<int> digits(k);
        for(int i = 0; i < x.size(); i++) {
            digits[i % k] += x[i] - '0';
        }
        auto carry = [&]() {
            for(int i = 0; i < digits.size(); i++) {
                if(digits[i] >= 10) {
                    if(i + 1 == digits.size()) digits.push_back(0);
                    digits[i + 1] += digits[i] / 10;
                }
                digits[i] %= 10;
            }
        };carry();
        while(digits.size() > k) {
            if(digits.back() == 0) digits.pop_back();
            else for(int i = k; i < digits.size(); i++) {
                digits[i % k] += digits[i];
                digits[i] = 0;
            }
            carry();
        }
        digits.resize(k);
        nums.push_back(digits);
    }
    vector<array<int, num_mods>> T(n);
    for(int i = 0; i < n; i++) T[i] = transform(nums[i]);

    vector<int> MD(k, 9);
    auto M = transform(MD);

    auto solve = [&](array<int, num_mods> X) {
        // map<array<int,
        // for(auto i : X) cout << i << " "; cout << endl;
        int ans = 0;
        for(int i = 0; i < n; i++) {
            // cout << T[i][0] << endl;
            map<array<int, num_mods>, int> cnt;
            for(int j = 0; j <= i; j++) {
                cnt[T[j]]++;
                array<int, num_mods> need;
                for(int t = 0; t < num_mods; t++)
                    need[t] = (X[t] - T[i][t] - T[j][t] + 3ll * mods[t]) % mods[t];
                ans += cnt[need];
                // cout << i << " " << j << " "; for(auto x : need) cout << x << " "; cout << endl;
            }
        }
        // cout << ans << endl << endl;
        return ans;
    };
    ll ans = 0;
    for(int i = 0; i < 3; i++) {
        auto X = M;
        for(int t = 0; t < num_mods; t++) X[t] = X[t] * 1ll * i % mods[t];
        ans += solve(X);
    }
    cout << (int)(ans) << '\n';
}

answer.code:11:65: error: too many initializers for ‘const std::array<__int128, 2>’
   11 | const array<ll, num_mods> mods = { MOD1, MOD1+3, MOD1+5, MOD1+7 };
      |                                                                 ^
answer.code:26:1: warning: ISO C++ forbids declaration of ‘main’ with no type [-Wreturn-type]
   26 | main() {
      | ^~~~