# include <cstdio>
	using namespace std;
	
	int n, m, i, j, x1, x2, y1, y2, nr, sol, k;
	int a[ 301 ][ 301 ], v[45001][5], pl1[301], pl2[301], pc1[301], pc2[301];
	
	int main () {
		freopen ( "mahjong.in", "rt", stdin );
		freopen ( "mahjong.out", "wt", stdout );
		scanf ( "%d%d", &n, &m );
		
		for ( i = 1; i <= n; ++i ) {
			for ( j = 1; j <= m; ++j ) {
				scanf ( "%d", &a[ i ][ j ] );
				x1 = a[i][j];
				v[x1][++v[x1][0]] = i;
				v[x1][++v[x1][0]] = j;
			}
		}
		
		do {
			nr = 0;
			for ( i = 1; i <= n; ) {
				k = a[ i ][ 1 + pl1[ i ] ];
				if ( k ) {
					if ( i == v[k][1] && ( 1 + pl1[i] ) == v[k][2] ) {
						x1 = i; y1 = 1 + pl1[i];
						x2 = v[k][3]; y2 = v[k][4];
					}
					else {
						x1 = i; y1 = 1 + pl1[i];
						x2 = v[k][1]; y2 = v[k][2];
					}
					if ( y2 == 1 + pl1[x2] ) {
						nr = 1; ++sol;
						a[x1][y1] = a[x2][y2] = 0;
						while ( !a[x1][y1] && y1 <= m ) {++pl1[x1]; ++y1;}
						while ( !a[x2][y2] && y2 <= m ) {++pl1[x2]; ++y2;}
					}
					else ++i;
				}
				else {
					while ( !a[ i ][ 1 + pl1[ i ] ] && pl1[i] < m ) ++pl1[i];
					++i;
				}
			}
			for ( j = 1; j <= m; ) {
				k = a[1 + pc1[ j ]][ j ];
				if ( k ) {
					if ( ( 1 + pc1[j] ) == v[k][1] && j == v[k][2] ) {
						x1 = 1 + pc1[j]; y1 = j;
						x2 = v[k][3]; y2 = v[k][4];
					}
					else {
						x1 = 1 + pc1[j]; y1 = j;
						x2 = v[k][1]; y2 = v[k][2];
					}
					if ( x2 == 1 + pc1[y2] ) {
						nr = 1; ++sol;
						a[x1][y1] = a[x2][y2] = 0;
						while ( !a[x1][y1] && x1 <= n) {++pc1[y1]; ++x1;}
						while ( !a[x2][y2] && x2 <= n) {++pc1[y2]; ++x2;}
					}
					else ++j;
				}
				else {
					while ( !a[ 1 + pc1[ j ]][ j ] && pc1[j] < n ) ++pc1[j];
					++j;
				}
			}
			for ( i = 1; i <= n; ) {
				k = a[i][m - pl2[i] ];
				if ( k ) {
					if ( i == v[k][1] && ( m - pl2[i] ) == v[k][2] ) {
						x1 = i; y1 = m - pl2[i];
						x2 = v[k][3]; y2 = v[k][4];
					}
					else {
						x1 = i; y1 = m - pl2[i];
						x2 = v[k][1]; y2 = v[k][2];
					}
					if ( y2 == m - pl2[x2] ) {
						nr = 1; ++sol;
						a[x1][y1] = a[x2][y2] = 0;
						while ( !a[x1][y1] && y1 > 0 ) {++pl2[x1]; --y1;}
						while ( !a[x2][y2] && y2 > 0 ) {++pl2[x2]; --y2;}
					}
					else ++i;
				}
				else {
					while ( !a[ i ][ m - pl2[i]] && pl2[i] < m ) ++ pl2[i];
					++i;
				}
			}
			for ( j = 1; j <= m; ) {
				k = a[ n - pc2[j] ][ j ];
				if ( k ) {
					if ( ( n - pc2[j] ) == v[k][1] && j == v[k][2] ) {
						x1 = n - pc2[j]; y1 = j;
						x2 = v[k][3]; y2 = v[k][4];
					}
					else {
						x1 = n - pc2[j]; y1 = j;
						x2 = v[k][1]; y2 = v[k][2];
					}
					if ( x2 == n - pc2[y2] ) {
						nr = 1; ++sol;
						a[x1][y1] = a[x2][y2] = 0;
						while ( !a[x1][y1] && x1 > 0 ) {++pc2[y1]; --x1;}
						while ( !a[x2][y2] && x2 > 0 ) {++pc2[y2]; --x2;}
					}
					else ++j;
				}
				else {
					while ( !a[ n - pc2[j] ][ j ] && pc2[j] < n ) ++pc2[j];
					++j;
				}
			}
		} while ( nr );
		
		printf ( "%d\n", sol );
		return 0;
	}