#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstring>
typedef long long ll;
const ll mod = 1000000007;
template <typename T> T Add(T x, T y) { return (x + y >= mod) ? (x + y - mod) : (x + y); }
template <typename T> T cAdd(T x, T y) { return x = (x + y >= mod) ? (x + y - mod) : (x + y); }
template <typename T> T Mul(T x, T y) { return x * y % mod; }
template <typename T> T Mod(T x) { return x < 0 ? (x + mod) : x; }
template <typename T> T Max(T x, T y) { return x > y ? x : y; }
template <typename T> T Min(T x, T y) { return x < y ? x : y; }
template <typename T> T Abs(T x) { return x < 0 ? -x : x; }
template <typename T> T chkmax(T &x, T y) { return x = x > y ? x : y; }
template <typename T>
T &read(T &r) {
    r = 0; bool w = 0; char ch = getchar();
    while(ch < '0' || ch > '9') w = ch == '-' ? 1 : 0, ch = getchar();
    while(ch >= '0' && ch <= '9') r = (r << 3) + (r <<1) + (ch ^ 48), ch = getchar();
    return r = w ? -r : r;
}
ll qpow(ll x, ll y) {
    ll sumq = 1;
    while(y) {
        if(y & 1) sumq = sumq * x % mod;
        x = x * x % mod;
        y >>= 1;
    }
    return sumq;
}
const int N = 110;
int n, m;
int len[N], f[N][N], s[N][N][N];
signed main() { //freopen("in.txt", "r", stdin); freopen("out.txt", "w", stdout);
    read(n); read(m);
    for(int i = 1; i <= n; ++i) {
        read(len[i]);
        for(int j = 1; j <= len[i]; ++j) {
            int x, y; read(x); read(y);
            for(int k = x; k <= y; ++k)
                ++s[k][x][y];
        }
    }
    for(int k = 1; k <= m; ++k) {
        for(int l = m; l; --l)
            for(int r = 1; r <= m; ++r)
                s[k][l][r] += s[k][l][r-1];
        for(int l = m; l; --l)
            for(int r = 1; r <= m; ++r)
                s[k][l][r] += s[k][l+1][r];
    }
    for(int k = 1; k <= m; ++k) f[k][k] = s[k][k][k] * s[k][k][k];
    for(int len = 1; len < m; ++len)
        for(int i = 1; i + len <= m; ++i) {
            int j = i + len;
            for(int k = i; k <= j; ++k) f[i][j] = Max(f[i][j], f[i][k-1] + s[k][i][j] * s[k][i][j] + f[k+1][j]);
        }
    printf("%d\n", f[1][m]);
    return 0;
}